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Universal Ammunition

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Tony: I'm out. Gimme, give me. You've got extra mags?
Rhodey: They're not universal, Tony!

An odd phenomenon in some video games with guns in that any ammunition you pick up works with either any gun whatsoever or an entire class of guns. In the real world, cartridges have a variety of different calibers, lengths and propellants based on a number of factors, including desired stopping power, target penetration, and the amount of recoil and gas pressure needed for a semiauto or automatic weapon to cycle itself (or, the other way around, prevent it from exploding in your face).

These cartridges are then loaded into clips and magazinesnote  designed for specific weapons, so that even if the cartridges are identical between two or more guns, you'll have to unload and reload one painstaking round at a time before you can take advantage of it; nevermind the question of where you're getting the empty magazines from. Sitting down and filling up mags is "not always an option" in a pitched firefight, and largely qualifies as an Acceptable Break from Reality. This trope is similar to One Bullet Clips since both of them treat ammunition like water that's just decanted into a container of the right type when needed; here the container in question and its contents can magically change depending on what it is being attached to, whereas there it's more about the way every magazine not actively in your weapon is immersed in the ammo-liquid until it is as full as possible.

Before adding examples please keep in mind that a lot of weapons from video games are based on real-life weapons. Many military and civilian weapons very intentionally use common "standard" ammunition sizes and magazine types (like the NATO 5.56 and 7.62 rounds for assault rifles and battle rifles, respectively). Most 5.56mm weapons use the magwell dimensions specified under the draft STANAG 4179, meaning one can take a magazine from any such weapon and use it in another. However, if the magazine is interchangeable but visibly different depending on the weapon (for example, a steel 30-round magazine for an M4 turning into a polymer PMAG when it's put in an HK416) it is still this trope. If two weapons that have interchangeable ammunition in real life use different ammunition in the game, it is an inverted example.

"Compatible magazines" is an important distinction: if a Luger, MP40, MP5 and Glock 17 all share a "9mm ammo" pickup, there's still behind-the-scenes magic going on. Let's say you pick up a 32-round MP40 magazine under the above. You can use it to reload the 8-round Luger, the 17-round Glock, and the 30-round MP5. This could only really work if you picked up the MP40 magazine itself along with four empty Luger mags, 2 empty Glock mags, and 2 empty MP5 mags. Obviously, you didn't just pick up nine magazines, eight of them empty, so instead of having magic transforming bullets you have a magic transforming magazine.

Note that most Energy Weapons' batteries/power sources, in contrast to the panoply of batteries for various uses in Real Life, are portrayed as universal. Just pop in a random battery and they're good to go (though it can be reasonably assumed that specialized batteries for energy weapons, if such are ever developed in real life, likely would be made to some sort of standard, judging by the efforts undertaken to standardize bullets and magazines for kinetic weapons).

In fictional settings, such as science fiction, this is sometimes purposely justified by declaring there has been a worldwide standardization causing an actual adoption of universal ammunition or some sort of literally universal ammunition that's capable of reconfiguring itself to completely differing weapons.

See also Bottomless Magazines, One Bullet Clips.

Inexplicable video game examples:

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    Action Game 
  • Despite the huge arsenal of weapons in Nuclear Throne, there are only 5 ammunition types. This leads to completely different weapons somehow sharing the same ammo pool, such as the Auto Crossbow and Disc Gun both using bolt ammunition.

    First-Person Shooter 
  • GoldenEye (1997) has two main types of ammo, pistol and rifle. No matter what pistol or submachine gun you use, it'll take the same ammo. Likewise, no matter what rifle you pick up, it'll take whatever rifle ammo you have. However, there are unique types of ammunition specific to certain weapons such as rocket ammunition for the rocket launcher or shotgun shells for the shotgun.
  • Perfect Dark and its prequel have more weapons with unique ammo types, but otherwise retain the same ammunition setup as in GoldenEye, changed only to add a third category for SMG ammo. Even funnier is that there are some alien weapons in the first game which draw from these pools (and some of them even have reloading animations of putting an extra glob of goo into the gun!) - good thing the Skedar chambered their handguns for 9mm, right?
  • Medal of Honor: Allied Assault has wildly different guns from four nations all accepting the same carts and mags if they're the same "type" (pistol, rifle, etc.). The original PSX game averted this for pistols and submachine guns (for instance, salvaged 9mm guns would not give you ammo for your .45 Colt or Thompson), but played it straight with rifles. The 2010 reboot switches to the standard modern system of weapons sharing ammo based on real-world caliber, and also allows you to ask certain allies for more ammo regardless of whether he would logically be carrying that kind of ammo on him.
    • In Medal of Honor: Vanguard, enemies sometimes drop ammunition boxes instead of their weapon, which always gives the player ammunition regardless of what weapon the player is using.
  • The World Is Not Enough handles this differently depending on platform. While the PS1 version identifies every ammo type specifically by what weapon it went for - so, for example, having several mags' worth of TMP ammo won't help you keep your P99 or silenced MP5 loaded - the N64 version instead identifies regular ammo types by caliber. For the most part, ammo is only shared by weapons that do, in fact, fire the same bullets in real life (ignoring the One Bullet Clips issues that result), but there are still some oddities resulting from the fact that ammo is only identified by its diameter, so for instance you're perfectly capable of keeping the 7.62x51mm MSG90 or SSG 3000 loaded by salvaging dropped 7.62x39mm AKS-47s.
  • Team Fortress 2:
    • Once upon a time, picking up any weapon dropped by a dead player gave you half of your maximum ammunition, whether it was like the Pyro's flamethrower, the Soldier's rocket launcher, the Demoman's bottle, a wooden bat, 150kg of metal in the shape of a minigun, or a dead fish. Spies could also somehow recharge their cloak meter with these same objects, as could the Engineer regain metal to build sentry guns and teleporters. Oddly, dropped hats gave no metal, despite them being made out of enough of the stuff to craft at least 36 weapons. With the Gun Mettle update, a dead player will drop both the weapon and a medium ammo pack. The dropped weapon instead can be freely picked up and used by another player of the respective class until their death or the end of the match.
    • Lampshaded in Poker Night at the Inventory. According to the Heavy, his minigun uses ammo with classified diameters so that his enemies cannot use it. It could be a case of not being able to manufacture more, but even then it's still absurd.
    • Team Fortress 2 Classic removed the ability to pick up dropped weapons from live TF2, and reverted the dropped ammo box at the same time, returning to live TF2's original absurdity.
  • Call of Duty:
    • Averted to a slightly unrealistic degree at times in the earlier games. Even the normal and sniper versions of a weapon cannot interchange ammunition; while in some cases like most bolt-action rifles this is at least slightly-accurate since attaching a scope made it impossible to reload them using stripper clips (ignoring that your character could just remove the bullets from those clips and load them individually), it's even the case when the weapons should use exactly the same ammunition loaded exactly the same way, like the Sten being nearly-impossible to replenish despite taking the same ammo as the MP40s every other German soldier drops, or a scoped Mosin-Nagant reloading with clips anyway (your character's hand dutifully clipping right through the scope to do so) but still not being able to take more from unscoped ones.
    • Call of Duty 4 changed this around and allows you to take ammo from any dropped weapon if it fired the same kind of bullet as what you already had, and if it isn't already the exact same gun you're using, the gun itself stays on the ground in case you want to swap for it. Somewhat oddly, you can also increase the amount of maximum ammo for a gun by carrying another one that shares ammo (such as the 5.56x45mm M16, M4, and/or G36C, which falls into this when you're using two guns that are clearly not using the same magazines). Multiplayer and later games are a bit stricter, where attachment differences don't matter, but what type of gun it is does - e.g. you can get ammo for your M4 with grenade launcher from dropped M4s with red dots, ACOGs, or nothing, but will be shit out of luck trying to take ammo from an M16, even one with the same grenade launcher attached. In singleplayer this isn't very limiting for the most part, as you typically have the same gun all your Red Shirt allies have (thus allowing you to replenish yourself from their guns when they die) or are given a unique gun with a ridiculous amount of ammo to start with (the silenced ACR with a red dot sight and heartbeat sensor from the MW2 mission "Cliffhanger" holds over a thousand bullets in total - more ammo than an entire fire team would be expected to have on-hand in reality), and stolen enemy guns are easy to keep loaded too because enemies are typically randomly given one of three or four guns dependent on the level.
    • Multiplayer in later games would occasionally go back to ridiculously strict requirements to pick up ammo from another gun on the ground - some games don't let you take ammo from a dropped gun, even if it's the same weapon with the same attachments, if the camo pattern applied to it is different from yours - but games since Modern Warfare 2 also allow this to be played ridiculously straight with the "Scavenger" perk - everyone you kill (except by explosive weapons in later games) will drop a backpack with one full magazine for whatever guns you're carrying, another piece of your primary equipment, and one special grenade. In Modern Warfare 2, this backpack also contains a 40mm grenade or four shotgun shells if your gun has the grenade launcher/shotgun attachment. Yeesh, good thing the enemy didn't know they were carrying all this stuff... Amusingly, the perk is also available in the singleplayer of Black Ops II, which is probably even more ridiculous than multiplayer, because New Game Plus combined with it allows you to replenish ammo for various one-off futuristic weapons by picking up packs dropped by people in a time period before those weapons even existed.
    • Call of Duty: Modern Warfare (2019) and onward handle this differently depending on mode and circumstances. Weapons identify their ammo by specific caliber, and so picking up ammo from a dropped weapon in single- or multiplayer requires it to use the same ammo as your weapon - otherwise, you're reliant on teammates dropping munitions boxes or running the Scavenger perk. Warzone, however, identifies ammo types more generally, allowing any weapon of a requisite category to use it regardless of what it's stated to fire in other modes: heavy ammo can be shared by a 5.56mm assault rifle, 7.62mm battle rifle, and 6.8mm machine gun, just as RPG ammo, despite its pickups being visibly based specifically on the RPG-7's rocket, can be shared by any launcher from the RPG-7 to a 40mm grenade launcher and, in the first Warzone, even a ballistic knife.
    • Call of Duty: Modern Warfare II even applies this to muzzle attachments. What attachments are available in that slot for a gun depends on the caliber it fires, but weapons of more than one caliber can share any given attachment. In some cases it makes sense at least at first glance, such as the 7.62 NATO battle rifles and machine guns able to interchange muzzle brakes and suppressors with the 7.62 Soviet assault rifles and machine guns, but other times it gets completely arbitrary - perhaps most ridiculously, as of Season 3, muzzle attachments previously exclusive to the "FTac Recon" in .458 SOCOM can be used with the M200 Intervention in .408 CheyTac. This also applies to ammo attachments to a lesser degree, as ammo types are shared between the 7.62 NATO and 7.62 Soviet weapons (e.g. leveling the RPK a little bit will unlock armor-piercing 7.62mm ammo for the Lachmann-762 and SAKIN MG38 as well).
    • Zombies mode also uses this, which is probably to be expected since it isn't even trying to be realistic. Save for purchasing a weapon from off the wall and then going back to purchase ammo, your only other option for replenishing ammo is the Max Ammo pickup randomly dropped by zombies that will refill everything you have, whether it's a revolver that predates either World War, a submachine gun from the 1960s, a belt-fed machine gun from the 2060s, or a retro-futuristic raygun developed by Nazi super-science.
  • Turning Point: Fall of Liberty suffers from a glaring lack of ammo commonality. No two of the game's many 9mm weapons can share ammo. In fact, if you had the scoped and unscoped versions of the same gun, they still do not share ammo.
  • In Enemy Territory: Quake Wars, the Strogg use the exact same pickup for all their ammo and their health restoration. This would normally fall under Justified Examples... except that the pickup in question was established in Quake IV to be a specially treated slurry of liquefied human remains, and could not conceivably function as ammunition for anything except a particularly disgusting squirt-gun. Even more glaring is that some Strogg weapons (namely the nailgun) use physical projectiles, as opposed to plasma/generic energy, so you couldn't even say the ammo's powering the gun's internal generator, unless it's also somehow used to fuel a replicator stored in the gun.
  • In Far Cry, the MP5 and P90 use the same ammo, with boxed "SMG" ammo found in the game having "9x19" written on it. Right ammo for the MP5, but absolutely wrong for the 5.7x28mm P90.
    • In the various sequels, all weapons of the same type (with distinctions for which slot they go in for 2) use the same ammunition and can get more by walking over any other weapon of its type dropped by dead enemies. This means, for example, as of Far Cry 4 the pistols are all simultaneously chambered in .45 ACP, both 9mm Makarov and Para, .44 Magnum, 7.63mm Mauser, .455 Webley, and .50 Action Express. And that the same ammo pickups feed sniper rifles chambered for 7.62x54mmR, .308 Winchester, .50 BMG, and a .700 Nitro Express hunting rifle. They apparently tried to justify this for the automatic rifles in Far Cry 2, where they all use 7.62mm bullets in real life (even going out of their way to include an obscure 7.62mm predecessor to the AR-18 rather than any form of M16), but they ignored the fact that the AK-47 doesn't use the same 7.62 bullets as the others; conversely, this also means that the player in that game can be carrying two 40mm grenade launchers or 12-gauge shotguns at the same time and not share ammo between them for no other reason than because one of them is being used in place of a pistol and the other in place of a rifle.
    • Most ridiculously, in Far Cry 2 the ammo pickup for the flare gun is shown as the same can of gasoline the flamethrower and Molotovs use.
  • Half-Life:
    • Half-Life's pistol and submachine gun use the same ammunition. This isn't a problem with regards to the Glock and MP5, using 9mm pistol ammo, although Fridge Logic arises in how Gordon transfers the ammo between guns (he likely does so the same way he transfers bullets between half-used magazines - that is, his HEV suit does it for him). However, the Hi-Def pack - an overall graphical upgrade - changes the Glock into a Beretta and the MP5 into an M4 assault rifle. That creates a new problem - the M4 uses 5.56x45mm ammo, not 9x19mm. Another problem comes when combining the Opposing Force expansion with the Hi-Def pack, which adds an M249 SAW that should share ammo with the M4, but doesn't. This was fixed in the Play Station 2 port, which used the hi-def models, added a separate ammo type for the M4, and does not include the weapons from Opposing Force.
    • Totally averted in Half-Life 2, as every weapon uses unique ammunition that even has a unique world model (so the submachine gun ammo appears as an ammo box correctly labeled as holding 4.6x30mm ammo which is visibly distinct from the ammo boxes for the pistol which are marked as holding 9mm, and grenades for its launcher are noticeably different from the hand-thrown ones). One Bullet Clips still apply, which is once again hand-waved as a function of the HEV suit.
  • BioShock 2 features various Rapture citizens carrying around the world's first custom-made .50 BMG Thompsons, so that their weapons can share ammo with Subject Delta's huge Gatling gun. Of course how the hell they could actually use a .50 BMG Thompson is never dealt with.
  • Averted in S.T.A.L.K.E.R., where there are some guns that use unique caliber suitable only for them, not to mention each gun has two or three different types of ammo for various situations. The game does occasionally feature unique versions of guns chambered for a different ammo type or, in later games, the ability to convert a gun chambering Warsaw Pact ammo to use the equivalent NATO caliber (and vice versa) by visiting a tech.
  • The pistol and minigun in Unreal and Unreal Tournament share ammo; likely in reference to this, both of their Secondary Fire modes just increased firing speed at the cost of accuracy. Later games gave the two weapons separate ammo pools, culminating in Unreal Tournament III's minigun firing Tarydium shards rather than conventional bullets.
  • Exhumed (a.k.a. Powerslave) has a variation in the Sega Saturn and Play Station versions in which the ammo pickups are all generic blue orbs that refill whatever weapon you are holding at the time, but the weapons themselves all have different ammo pools beyond that.
  • In Guns of Icarus Online, players can equip special ammunition to apply various advantages and disadvantages to their weapon. Special ammo works in any weapon, regardless of whether the weapon is firing bullets, missiles, or burning gasoline.
  • PlanetSide 2, unlike its predecessor, uses universal ammunition for its weapons. An engineer dropping an ammo pack will refill anyone's ammo; be it the slugs for a Gauss Rifle, caseless ammo for the Mini Chaingun, the plasma batteries for a Lasher, or the high-explosive rockets for a Decimator.
  • PAYDAY 2 goes to both extremes.
    • On the one hand, your primary and secondary weapons use separate ammunition pools, even when they should be reasonably expected to share ammo - say, you can't double up on mags for the CAR-4 or AMR-16 by carrying a Para as a secondary, and a single version of a handgun or submachine gun used as a secondary weapon will have a separate ammo pool from two more of the same gun used as a primary.
    • On the other, ammunition pickups restore ammo for almost all weapons, though different weapons and ammo types replenish at different rates; a box of ammo from a dead street cop will probably give you anywhere between three to twelve bullets for an assault rifle, but only one or two extra shells for a secondary shotgun, possibly not even that if loading it with slugs or explosive shells. An attempt at justification can be seen in the ammo pickups having multiple ammunition boxes clustered together, but that does not explain why a player who only needs shotgun ammunition somehow makes all of the handgun ammo from a pickup vanish, or why a policeman only armed with a single 9mm pistol is also carrying boxes of shotgun shells and 5.56mm bullets on him... or why those shotgun shells and 5.56mm bullets can also turn into rounds of nearly any other caliber, including 9x18mm Makarov, 4.6x30mm, 7.62x39mm, .30-06 Springfield, or even 25 and 40mm grenades. Nor does it explain how a player filling up on saw blades from an ammo bag, which looks to be filled only with magazines for specific assault rifles, somehow reduces the amount of .50 BMG ammunition available for a Thanatos-equipped player.
  • Blockstorm uses a system similar to the above-mentioned Call of Duty's Scavenger perk. Every time a player dies they drop a backpack, and any other player who picks that up before it disappears gets one full magazine for both of their weapons and one more round for or instance of their explosive weapon, regardless of what either player is using or if the dead player even still had ammo before they bit it. The backpack also gives a full refill for the placeable team-colored blocks, even if the killed player had none left themselves. This gets particularly silly following the update that added Humongous Mecha to the game, where they can pick up those backpacks to get more Arm Cannon-gatling ammo and another rocket, too.
  • In 8Bit Killer, you have a single type of ammo which is used by all weapons in your arsenal save for the handgun. Even a rocket launcher accepts these bullets.
  • The Battlefield series has generally zig-zagged this. Individual weapons tend to have their own specific ammo counts, even in games letting you use two of the same type of weapon loaded in the same manner, e.g. Battlefield 4 not letting you borrow shells from your secondary "Shorty 12G" to load up any of the primary shotguns like the 870 or SPAS-12. The Support class's Ammo Box, on the other hand, will refill ammo for anyone on your team regardless of what weapons they're using - to use BF4 as an example again, an Assault player with a 5.56x45mm rifle and 40x46mm grenade launcher, a Recon with a 5.8x42mm rifle and a .357 Magnum revolver, an Engineer with a .45 ACP submachine gun and 5.7x28mm handgun, and a Support with a 7.62x54mm machine gun and 25x40mm grenade launcher will all replenish ammo for all of their weapons from the same ammo bag, with only the explosive weapons regaining ammo at a slightly slower rate.
  • The End Times: Vermintide and Vermintide II: Ammunition works for every weapon that doesn't run on Overheat instead, from longbows to pistols and even the Trollhammer Torpedo. Hand-waved by dialogue suggesting that ammo crates contain a bit of everything:
    Victor: Shot, quarrels, arrows — a fine supply!
  • X-Men: The Ravages of Apocalypse: The shotgun and chain-gun use the same ammunition, the latter using it much less efficiently.

    Platformer Games 
  • In Duke Nukem: Manhattan Project, you have 3 different ammunition types: Ammo, Pipe Bomb, and Energy. Ammo is used for your Desert Eagle, Shotgun, and Assault Rifle, though the minor pickups only show 3 Desert Eagle rounds (the Major pickups show one of each round). Pipe Bombs are used for Pipe Bombs and the RPG. Energy is used for the De-Mutator (a glob-throwing weapon that de-mutates any mutants you run across) and Pulse Rifle.

    Real Time Strategy 
  • In Star Ruler, all ships draw from an abstracted ammo supply with no attempt to distinguish types. Given that you can have any number of ships in varying sizes from fighters to planet-sized (or bigger!) super-battleships, trying to manage individual ammo types would be a real pain in the arse anyway.
  • In Men of War, it is both averted and played straight at the same time. On the one hand, different weapon types requires different ammo, you cannot just stick ammo for a pistol in a 40mm autocannon, or ammo for a .30-cal into a .50-cal machine gun. On the other hand, ammo can be used across any gun as long as they are of the same type, leading to a Colt 1911 (chambered for .45 ACP) being able to use ammo taken from an enemy with a Luger (chambered for 9x19mm).

    Role-Playing Games 
  • Bloodborne: Quicksilver Bullets are used for all of your firearms. At first it can be justified in that the bullets are made of liquid metal and can change shape to fit the gun, until you see they also can be used with a flamethrower, a cannon that shoots explosive cannonballs, or magical tools that very much aren't guns.
  • Irvine in Final Fantasy VIII has ammo for his Limit Break, but these work for all the guns he can equip in the game. This is not as inexplicable since you custom-make all of his weapons yourself, with the exception of his starting weapon, which the first upgrade is created from by using it as a base. In this case, you're modding the rifle to the ammo, most of which you can make yourself as well.
  • All weapons in Fallout that use the same caliber take the same ammunition. The issue of different cartridges in the same caliber is ignored, magazines/clips/belt links don't need to be kept track of, and characters seem to load mags in the heat of combat.
    • Possibly justified by the fact in a world with definitely limited ammunition guns would be modified to accept the most common types.
    • Fallout 2 has a car that can be recharged by both Small Energy Cells and Fusion Batteries - themselves used as clips for a wide assortment of energy weapons.
    • Due to a bug in Fallout 2, the P90 expy gun comes loaded with 9mm ammo, which is extremely rare and was only designed to be used in this one gun (it isn't even the only specialized 9mm ammo, either - elsewhere in the game is a Mauser that takes 9mm (ball) ammo). However, once emptied, it then takes extremely common 10mm ammo.
    • In Fallout 3, Lincoln's Repeater (an authentic Henry Rifle) uses the same ammo as the .44 revolver. A .44 Magnum round might fit inside a Henry rifle, but the rifle's pin would hit the wrong part of the cartridge, missing the primer entirely and thus failing to fire. Even if it could fire, the higher pressure would likely destroy the rifle in short order.
    • The .32 Pistol and Hunting Rifle both use .32 caliber ammo, however the rifle is much more powerful than the pistol. The pistol is probably the weakest weapon in the game. This is because the Hunting Rifle is actually firing .308 projectiles, and someone accidentally set it to use the wrong ammo; even if it weren't a glitch, the long-barreled rifle with a sealed chamber would be able to fire the bullet with much more energy than the tiny, unsealed revolver anyway.
    • Fallout: New Vegas has several weapons which share ammo pools, some more sensibly than others. For instance, it's not too far out of the question that the 9mm SMG uses the same round as the 9mm pistol, but there's a few questions as to why a superheavy machine gun loads handgun rounds and two of the miniguns load revolver rounds. The most questionable universality in ammo might be that of the flame weapons: weapons that fire flamer fuel can somehow use this ammunition type to produce a flamethrower's flames, an incinerator's arcing fireballs, or most oddly, a flare gun's magnesium flare.
      • A high enough Science skill will allow you to use workbenches to convert the three main types of energy weapon ammunition between each other, effectively invoking this trope yourself. You can also transfer the energy in fission batteries to small energy cells (then covert them to whatever type you need)—which mysteriously creates five charged cells for every drained one the recipe requires.
    • Fallout 4 allows you to modify some guns to use different ammunition types that can increase or decrease their attack power, which is useful for when you have an excess of one ammo type but a shortage of another.
  • Arcanum: Of Steamworks & Magick Obscura:
    • All firearms, barring a few exotic examples, take the same bullets. Larger guns just shoot more than one at a time. Of course, the Bullets schematic only requires (some of) the ingredients for black powder, so it's unclear just what exactly you're shooting.
    • Particularly egregious with flintlocks, which shouldn't even fire modern cartridges. Muzzle-loading guns with flintlock mechanisms require gunpowder and a pure lead bullet rammed down the barrel, with some loose powder poured into a priming pan. This is all very fiddly and takes more time without powder-measuring flasks or prepared shot-sets.
  • On a larger scale in EVE Online, one unit of a certain "size" of projectile ammunition can be chambered in up to five calibers. For example, one unit of "Large projectile ammunition", meant to be fired from battleship guns, can be used interchangeably in Dual 425mm, 650mm, 800mm, 1200mm, and 1400mm guns. Also, a unit of ammunition unloaded from an 800mm autocannon takes up the volume as ammunition unloaded from a 1400mm howitzer.
  • Averted in 7.62mm High Caliber, with each gun taking the proper caliber and many calibers coming in multiple brands and types that can be mixed and matched in the magazines, and each gun takes its own magazine. One error is that the Mauser pistol and carbine take 7.62x25mm Tokarev ammo (which will load in a Mauser, being the same size as its 7.63x25mm Mauser ammo, but are too powerful to safely use with it).
  • Played absurdly straight in Persona, where your first ammo pickup is "9mm bullet" (followed by "12ga bullets" before moving on to "Tranquilizers", "Mage Killers" and so on) which you can equip with any gun type, be it an SMG, a shotgun, or an assault rifle.
  • Digital Devil Saga: The same ammunition can be used in not only handguns and rifles, but shotguns and grenade launchers.
  • Radiant Arc:
    • Lexie requires arrows in order to fire her bow or use bow skills. However, there is only one type of arrow despite the many bows in the game.
    • Downplayed for Nuria's guns. There are bullets for specific gun types, but that means all guns of the same type can use the same ammo, regardless of their actual chamber size.

    Simulation Game 
  • Averted in Operation Flashpoint and its Spiritual Successor ARMA. Unless the type of ammunition is used in a whole closely related family/series of firearms, you'll have to find appropriate ammo for each gun. You won't have much luck firing an AK-74 with a magazine of M16 bullets. As noted, however, related firearms can take the same ammo (most assault rifles of Western origin in the series use the same magazines as the M16, for example).
    • ARMA III reverses this, as most weapons actually do take the same bullets as the equivalent weapons from the other factions (basic rifles taking 6.5mm for the major factions and 5.56mm for the indigenous forces, light pistols taking 9x21mm, heavy pistols .45 ACP), but use different, incompatible magazines (for the biggest example, FNP mags versus Rhino speedloaders for the .45 pistols) that can't be exchanged except by downloading a mod that lets you transfer ammo between mags; before an update alongside the Contact DLC in 2019, even different versions of the same weapon generally couldn't exchange mags, such as the inability to use the MXSW machine gun's hundred-round mags in the MXM marksman's rifle, and with mags that were compatible changing camo patterns to match the gun they're loaded in until the different colors were made separate with that update.
  • In FTL: Faster Than Light, there are missiles and drone parts which are consumed by firing a missile-based weapon and deploying a drone schematic, respectively. The same missile can be used to fire a usual rocket, a bigger rocket that can leave a nasty hull breach, a bomb that teleports straight inside the ship or a packet that instantly repairs one of your systems. The same drone part can be used to create a tiny bot that rides around your ship repairing systems, a scary tank-bot that flies towards your enemy to wreak havoc inside their ship, a tiny ship that constantly attacks the enemy ships with projectiles or a defence turret that shoots down incoming projectiles.
  • City-Building Series: Done with people standing in for ammunition: The working populace (usually around half the non-elite population) can be assigned to any job (potters, cheesemakers, musicians, firemen, etc.) with no loss of productivity. Elites cannot be used, however, as they serve the city differently (such as paying far more taxes or providing the city's military).

    Survival Horror 
  • A recurring trope in the Resident Evil games:
    • Though justified in the main game of Resident Evil 2 (both Leon's VP70 and Claire's Hi-Power do, in fact, use the same type of ammunition in real life, and the issue of different magazines is mostly avoided by pickups clearly being boxes of loose bullets), it is invoked poorly with Claire's bonus weapon, the Colt .45 revolver. Granted, it's to fit the whole "cowgirl" theme along with her outfit, but as its name suggests, the revolver uses .45 Long Colt rounds, not 9mm ones.
    • It's invoked even more poorly in Resident Evil: Gun Survivor, where all four of your available handguns use 9mm rounds, which includes the Nambu pistol, a gun that was chambered exclusively in 8X22 mm. This is very weakly Hand Waved by the gun being described as "Custom," even though a standard Nambu pistol would likely self-destruct if one ever did go to the trouble of rechambering it for 9mm without strengthening the receiver.
    • In Resident Evil 5, the Skorpion, MP5, AK-47, and SIG 556 all take the same "machine gun" ammo despite being chambered for very different rounds (in fact, it's odd that the pistol ammo, which, due to being used in the Beretta 92FS, is implied to be 9mm Parabellum, doesn't work in the MP5, which takes that exact round IRL). This also happens in Resident Evil: Revelations.
    • Averted in Resident Evil 6: The different types of ammo are classed by caliber rather than what type of gun they're used for, meaning that the same 9mm ammo used in most characters' semiauto pistols can be used in Ada and Piers' submachine guns, Helena's 10-gauge Hydra shotgun takes different ammo than the 12-gauge shotguns other charactes use (the same is true with Piers' 12.7mm anti-materiel rifle and the other 7.62mm sniper rifles, and the game's two magnums, the Elephant Killer (.500 Smith & Wesson) and the Lightning Hawk (.50 Action Express)), and the 5.56 ammo used in assault rifles can't be used in any other type of gun.
    • Resident Evil: Revelations 2 returns to the system of splitting up ammo by gun type rather than caliber, but this time has its three submachine guns and two assault rifles take different types of ammo rather than having them both use "machine gun ammo."
    • There are three handguns in Resident Evil 7: Biohazard: an M1911, a Glock 17, and a Makarov PM. In the real world, these guns are chambered respectively in .45 ACP, 9x19 Parabellum, and 9x18 Makarov. In the game, they all magically use the same ammo.note 
  • The first Parasite Eve game has this. The only unique ammo is for the rocket launcher. Otherwise, you just have generic bullets. 9mm Parabellum = .45 ACP = 12 gauge = 7.62x51mm = 5.56x45mm = 40mm. For those who don't know ammo, pistol ammo = bigger pistol ammo = shotgun shell = rifle ammo = smaller rifle ammo = grenade.
    • Averted in Parasite Eve 2, where each ammo type is Color-Coded for Your Convenience. This even gets lampshaded by one of the NPCs, who notes that another character jammed a pistol by trying to force the ammo from a different pistol caliber into it.
  • The third game in the Dead Space series exchanges the previous games' "each gun has its own ammo type" system for this trope. Partially it was explained as a simplification for the new weapon crafting system, but the fandom reacted with They Changed It, Now It Sucks! (coupled with Lying Creator, as the initial Word of God was that this was only there for the demos).
  • The first ObsCure game has pistol and shotgun ammunition used across all weapons in each category. It's justified for the shotguns, which are all presumably 12-gauge, but the pistol ammo is used in everything from the old pocket pistol you find early on to the custom heavy pistol you take from the principal's safe to the Hand Cannon magnum revolver, which all vary widely in power. The second game averts it, with each gun using different ammunition, but the spinoff Final Exam goes even further and has all guns, from the pistol to the rocket launcher, use the same generic ammo.

    Third-Person Shooter 
  • In darkSector this is played pretty much straight with everything but the starting pistol, which only shares ammo with its own burst-firing upgrade; the Klin PP9 (9x18mm), AKS-74U (5.45x39mm) and G36C (5.56x45mm) all share an ammo pool, as do the Webley Mark IV revolver (9x20mm rimmed) and the SOCOM 16 rifle (7.62x51mm NATO).
  • Zig-Zagged by Tomb Raider. Each of Lara's weapons (bow, handgun, shotgun and rifle) use a different type of ammunition. However, all upgrades use their same respective ammunition, regardless of what stage you have them upgraded to. This is justified with the bow and shotgun, which don't change to forms that use completely different ammo, but is played ridiculously straight with the pistol and rifle, which do: Lara replaces her Beretta 92 (9x19mm Parabellum) with an M1911 (.45 ACP) and then somehow upgrades that M1911 into a Desert Eagle (.50 Action Express), while the rifle starts as a Type 100 (8x22mm Nambu) and is eventually turned into an AK-47 (7.62x39mm Soviet) and then some strange combination of it and an Ultimax 100 Mark 3 (5.56x45mm NATO). She also uses the same grenades for the rifle's grenade launcher to create "grenade arrows" (though that one is arguably justified). Also, all previous modifications (padded stocks, port-vented slides, etc.) automatically carry over when Lara upgrades her weapons - even in the above case of replacing her Beretta with the 1911 rather than upgrading it into one.
  • In Red Dead Redemption, each of its 21 firearms are in one of 6 categories: Revolvers, Pistols, Rifles, Repeaters, Sniper Rifles, and Shotguns. Each category has an associated ammunition type (e.g. shotgun ammo for shotguns) which is universal across all weapons in the category.
  • Remnant: From the Ashes: Ammo comes in two forms: handgun ammo, and long gun ammo. Each will fit anything in their category, from pistols to shotguns to sniper rifles to grenade launchers to crossbows to future-tech energy weapons to magical replicas made by fairies.
  • Resident Evil 4: Ammo, for the most part, is totally interchangeable within any weapon of a certain classification. This leads to the 5.7x28mm Five-seven firing the same 9x19mm Parabellum as Leon's custom "Silver Ghost" and the C96. Furthermore, the magazines are the same size for each gun, but the ammo cap for each gun can be upgraded. Is Leon putting two mags in on top of each other?
    • Inverted in the case of the TMP as compared to the handguns. An actual Steyr TMP fires standard 9x19mm Parabellum rounds, the same as what the ammo pickups for the handguns identifies them as firing, but the in-game TMP uses its own rounds separate from those for the handguns. This is justified with the series' catch-all Hand Wave that the rounds for your TMP are "custom".
  • The Sniper Elite series applies this inconsistently: while each individual weapon has its own individual ammo pool, save for running over a dropped weapon while you already have another of that weapon on you, ammo pickups are universal based on what slot a weapon goes in, no matter how unlikely. A German soldier with an MP 40 may have a very small handful of 9x19mm bullets as used in that MP 40 - and depending on each game's preferences it's a toss-up whether what bullets he does have will actually be usable in an MP 40 or only in the Luger or Welrod pistol - while it's far more likely for him to have a dozen or so rifle bullets in anything from American .30-06 to Japanese 7.7x58mm.
  • Warframe: There were four ammo types — pistol, rifle, shotgun, and sniper — Color-Coded for Your Convenience. How universal is it? All sidearms/secondaries share the 'pistol' ammo type. Aside from actual pistols this category also includes shotgun pistols, SMGs, throwing knives, crossbows, laser guns, handheld rocket launchers, small flame throwers, remotely detonated sticky bombs, and bits of mutated flesh that burst open on impact to release toxic gas. A Grineer Assault Rifle and Corpus Plasma Rifle can even run off the same rifle ammo pack. Despite the fact one shoots bullets and the other shoots plasma bolts. An update changed the ammunition system to an even more egregiously universal system, where any weapon designated a primary uses one ammunition type and secondary weapons use another, with the only difference between weapons being how much ammo per pickup there isnote .
    • And then there are "ammo mutation" mods, that, when equipped on a weapon, can convert any ammunition pickup into the relevant ammunition, so you get primary ammo from secondary ammo pickups, and an Attack Drone designed to act as an Item Caddy that can do the same for all your weapons. Protea’s Dispensary can grant and Lavos’ Transmutation Probe can convert ammunition to a universal type able to work in everything from everything above to BFGs meant for destroying spacecraft.
  • Max Payne 3 uses this, in contrast to the previous two games where only shotguns loaded with loose shells could share ammo; weapons here have their ammunition differentiated by the class of weapon, so e.g. the 7.62x51mm FAL can take ammo from the 7.62x39mm AK or 5.56x45mm MD-97L.
  • Ghost Recon:
    • Wildlands has weapons with individual ammo counts - e.g. dropping your nearly-full assault rifle for a different one used by an enemy will leave you with only a handful of shots for the new one - but also has enemies that drop pickups which give ammo for whatever you're currently carrying.
    • Breakpoint has separate classes of ammo with their own pickups, but only has seven ammo types: 9mm, .45, 12-gauge, 5.56, 7.62, .338, and "shells" (40mm grenades). This means a lot of weapons use ammo types that don't make any sense because that's the closest the game has to what it uses in reality, like the Five-Seven and P90 (both using 5.7x28mm in reality) using 5.56mm ammo, the Desert Eagle using .338 rounds that are otherwise exclusive to sniper rifles (and which is split between guns that actually fire .338 and those that are turning the same ammo into .50 BMG), or the 7.62x35mm Honey Badger, 7.62x39mm AK-47, 7.62.51mm MK17, and 7.62x54mmR SVD-63 all sharing the same ammo.

    Turn-Based Strategy 
  • In Jagged Alliance 2 all 7.62mm calibre weapons of WarPac/ChiCom origin use the same ammunition - 7.62mm, which would be logical, except there are three kinds of 7.62mm Warsaw Pact ammunition in real life: 7.62x54mmR, as used by the Dragunov and most of their MGs, 7.62x39mm as used by the AK-47/AKM and their relatives, and 7.62x25 used by the PPSh/Type 65 and other pistol type weapons. They are definitely NOT interchangeable; the second numbers denote case length, which means the first one would be more than twice the size of the chamber for the last. This was eventually fixed in the v1.13 modification.
  • While normally being pretty faithful to Real Life World War II weaponry, Silent Storm does have a few odd-balls. For example, some submachine guns can be reloaded by equivalent bullets used by machine guns (submachine gun mags take up 2 vertical Grid Inventory squares, while machine gun clips take up 4). One has to wonder how a large circular magazine fits into the normal-sized mag housing. The same is also true for the Energy Weapons that become available late in the game. The handheld versions are bazooka-sized, but there are also energy-armed Panzerkleins. All the mags for these are large (4 squares) but carry only a charge for a single shot. However, an extremely-rare Random Encounter can result in you getting your hands on an energy assault rifle, which uses rifle-sized magazines (1 square) with 50 shots in each. Once you give the rifle to the quartermaster as the base, you can get unlimited 50-shot mags that also work with any energy weapon. So, instead of lugging around huge canisters that only offer you a single shot, you can carry 4 mags for 200 shots in the same space.
  • Downplayed in Aurora when it comes to missiles. Every launcher can launch missiles equal to and smaller than the size of the launcher, but there is a Min-Maxing potential to encourage using the missiles they're made for. For instance, smaller launchers are quicker to reload, fire control designed for one type of missile will lose much of its efficiency if used for launching smaller ones (fighter fire controls tend to be poor resolution and small size so they are much shorter-ranged than escort/capital ships, and that could mean the difference between pounding enemy from a safe distance or entering the range of his own anti-ship missiles).
  • Girls' Frontline makes ammo management an important part of battle, but has it all as a simple, generic resource that all of your Tactical Dolls draw from when they resupply. You can have an echelon made up of girls using weapons with diverse and unique ammo types like a Nagant M1895 (7.62x38mmR), CBJ-MS (6.5x25mm), AAC Honey Badger (7.62x35mm), H&K G11 (4.73x33mm), and LWMMG (8.6x63mm), and they can all simply deduct a certain amount from your total ammo supply to fight with, with the only difference being exactly how much they each carry at once. That's also not getting into the fact that ammo as a resource is also used in the production of T-Dolls, despite the fact that there's no reason for any to be used until you actually have them and send them into battle.

    Wide Open Sandbox 
  • Most Grand Theft Auto games play this trope straight. A particularly egregious example is the Gusenberg Sweeper from Grand Theft Auto V, which is a Thompson submachine gun that inexplicably shares ammo with belt-fed machine guns.
  • Terraria has a very small selection of ammunition types, but said ammunition feeds a rather diverse variety of guns. For instance, standard Musket Ball ammunition will fire from muskets just fine, but it will also feed BB guns, revolvers, Uzis, shotguns, sniper rifles, and a half-minigun half-shark monstrosity.
  • Unturned downplays this. All guns use specific magazines (some, like the Military and Ranger assault rifles can use their respective category mags, and the Nightraider and Fusilaut can employ both Ranger and Military magazines of all kinds) that have to be pre-loaded. However, the magazines are reloaded with boxes of ammunition divided in classes. This ammo fits the mag once combined with it and can't be removed afterwards. In Unturned 2.0 the boxes were single items and filled each magazine by a certain amount dependent on the gun's damage per shot, but that was changed in 3.0 into bullets being counted individually inside the boxes.

Justified video game examples

    First-Person Shooter 
  • Borderlands has over 17 million guns, with Universal Ammo for each type of gun. The same bullets do different things, from explode to multiply, based on which gun they are loaded into, and can appear in a wide variety of clips (especially in 2), from energy cells for Maliwan or Hyperion sniper rifles to chunky wheels full of bullets for Jakobs ones. Each Vault Hunter carries a storage deck that can deconstruct, store, and reconstruct all of their guns, ammo, relics, etc; it isn't much of a stretch to think that it can create new custom ammo. This is explicitly the case with Tediore guns from Borderlands 2 onward; they explode and are reconstructed with full ammo rather than reloaded.
    • Salvador's class ability allows him to dual-wield guns and regenerate health and ammo. Naturally his class mod is a second storage deck.
    • Also justified in the case of E-Tech weapons in Borderlands 2, which fire everything from energy blasts to exploding swordsnote , even when they've got a Bandit clip that supplies clearly visible bullets: Zed explains during the "this is how E-Tech works" sidequest that E-Tech uses eridium-based technology to turn bullets into "things that ain't bullets", so presumably the laser blaster uses two bullets at a time because firing it involves converting two bullets into the death beam.
  • The Vanu Sovereignty in PlanetSide chamber the same type of ammunition (batteries) for their main weapons, as they all need similar levels of power. Their anti-tank laser cannon however, requires a much larger battery pack. Almost all handheld projectile rifles and pistols are chambered in 9mm ammo, bar sniper rifles, allowing a Terran Republic soldier behind enemy lines to reload his Mini Chaingun with ammo looted from New Conglomerate Gauss Rifles, for example.
  • Deus Ex: Invisible War takes this trope to the extreme. Anything that uses ammunition uses the same ammunition as everything else. The in-game explanation is that ammunition is reduced to a slurry of nanomachines that form into the proper ammunition for the weapon. This includes battery packs, flame thrower fuel, regular bullets, and even rockets. The creative reason behind this is that the inventory system got simplified, and carrying 20 types of ammo didn't sound appealing when you only had 7 spaces. This has the major drawback of burning your ammo with one gun, or even doing too much shooting late in the game means you're screwed, since you can still only carry about as much ammo as you could in the first game but that limited supply is stretched across four or five guns now.
    • Averted in the first game, and wasn't an issue because ammo was stored in a Hyperspace Arsenal (your coat) separate from the normal Grid Inventory. That said, pistol and sniper ammo were simply cartons of loose bullets rather than magazines. That's One Bullet Clips for you (on top of an attachment increasing the mag size of a specific weapon.
    • Human Revolution averts this even further, as ammunition takes up inventory space and almost every weapon requires specific ammunition; only very similar weapons like the regular and double-barrel shotgun or regular and silenced sniper rifle use the same ammo. One Bullet Clips are still present.
  • The Blake Stone games have all the weapons using the same ammo. Justified in that all the weapons are energy-based and the ammo is energy packs. Just don't go too crazy with the more ammo-hungry guns that you have to resort to using your emergency self-charging pistol.
  • The Doom series: the first two games had four types of ammunition for six guns (seven if you include the second game's super shotgun). The Plasma Gun and BFG share ammo, as do the aforementioned super shotgun and the original shotgun, which are both justified as the former two are both energy weapons powered by battery packs and the latter two are fed with loose shells, is justified. The pistol and chaingun also share ammunition, which is less justified. Doom³ averts the trope entirely, as excluding the double-barrel shotgun added in Resurrection of Evil, which shares ammo with the base shotgun, every weapon has its own unique ammo supply - even the pistol, submachine gun and chaingun which all fire bullets but have their own supplies. Doom (2016) goes back to the style of the first two games, using four ammo types for seven guns and two special ammo types for the special weapons.
  • The Wolfenstein series starting from Wolfenstein 3-D uses this trope, but for the most part only when it makes sense.
    • Wolf3D in particular only had three guns, two of which were based on real guns (the P08 or P38 pistol, depending on the system, and MP40 SMG) that do both use 9mm cartridges, though not from the same magazines - the minigun shares ammo with them too, but then again it is fictional. Later ports of the game add a rocket launcher and flamethrower weapon, each of which use separate ammo types from each other and the regular guns.
    • Return to Castle Wolfenstein has more ammo types, but is still careful to only let those guns that actually used them share - the returning Luger and MP40 all use 9mm Parabellum rounds, as does the British Sten, while also adding .45 ACP rounds for the Colt 1911 and Thompson SMG, and 7.92mm Mauser rounds for the Mauser rifle and FG 42. Other guns, like the Panzerfaust, flamethrower, tesla cannon and Snooper Rifle, each have their own ammo types, and you're not going to be pilfering more for them from the corpses of your enemies unless you stole the gun from one in the first place. Interestingly, the Venom gun has its own unique ammo supply, which is justified but in two entirely-incompatible ways - the in-game operations manual you can find before you get it states that it uses a specific variety of 7.92mm ammo that the Mauser and FG 42 presumably are not using, while its ammo pickups are identified as 12.7mm (i.e. .50-caliber) when you grab them.
    • The 2009 game and everything coming afterwards averts the trope entirely, where absolutely nothing shares ammo with anything else and most even get a second ammo type to switch between with an upgrade of some variety. The closest you get is that battery stations on the walls can be used to recharge anything that fires energy, be it the Laserkraftwerk, the AR Marksman's secondary fire, or even dismounted MG 60 machine guns.
  • Half-Life: The gluon gun and tau cannon share the same (nuclear) battery packs. According to the Half-Life wiki, these weapons are powered by a revolutionary miniature nuclear reactor fueled with depleted uranium - the contents of said battery packs.
  • Partially subverted in Star Wars: Dark Forces and its sequels; despite almost all of the weapons being energy-based (and able to be recharged from the same charging stations in Jedi Knight II onward), they use two different kinds of battery packs/cells - generally, energy cells power pure energy weapons like blaster pistols and rifles, while power cells from Jedi Knight: Dark Forces II onward go towards things that still use energy, but either a different type than blasters use (like the disruptor rifle or concussion rifle) or use power to propel or enhance a kinetic projectile (like the bowcaster and the heavy repeater). The main exceptions are the Dark Trooper assault cannon, which uses two different types of ammo exclusive to it, and the explosives, which are individual units.
  • In Star Trek Voyager: Elite Force Federation weapons use energy, while the those of the Delta Quadrant aliens run off dilithium crystals.
  • The '90s Battlezone games' Hover Tanks feed their machine guns, cannons, rockets, mines, extras from mines to the Phantom VIR and even energy weapons from the same "nano-ammo" supply.
  • Serious Sam's shotguns always share ammo. The Minigun also shares ammo with the Tommy Gun in 1 and the Uzis in 2 - NETRISCA's info screen for them specifically mention the latter two are re-chambered for 5.56mm rounds, while the former is a man-portable version of a 5.56mm Minigun. Inexplicably, Sam 3 gives the minigun its own ammo supply, even though its Assault Rifle is still firing the same ammonote .
  • Soldier of Fortune II has weapons draw from the same ammo pool depending on caliber - the 9mm SMGs all use the same ammo, the .45 ACP Grease Gun instead draws from the ammo pool you feed the M1911 and Mk 23 with, and the AK-74 shares ammo with the other 5.56mm assault rifles because it's noted as having been converted from its original 5.45mm cartridge to 5.56mm. There are still some oddities, though, such as the Desert Eagle sharing the same ammo as the other two handguns (no .45 ACP version of the Desert Eagle exists in reality), and none of the grenade launchers share ammo (realistic in the case of the XM29's 20mm grenades, but the M203 and Hawk both use the same 40mm ones in real life).
  • TRON 2.0 takes place Inside a Computer System, which justifies the trope by having all weapons being "primitives" or "programs" that draw upon a common energy supply. The player's Disc primitive costs no energy to use, and is versatile enough that running completely dry on energy is not crippling.
  • Left 4 Dead justifies this: all guns have separate ammo pools and replenish that or get upgraded ammo from the same pile/box, but they are all clearly shown to contain a variety of different types of ammo (even the buckets of bullets you usually see at the start of the L4D1 campaigns visibly contain several different varieties of magazine and a few loose rifle bullets). There are also a few weapons that cannot be reloaded from the ammo piles but can get explosive or incendiary ammo, specifically the grenade launcher and M60.
  • Metroid Prime: Hunters has actual nanotech-based Universal Ammo that fits all of your special weapons. Only Samus' missile launcher uses different ammo. Since all the other guns are at least partially energy weapons, it's a bit more believable, though, as the ammo itself probably doesn't need to shape itself to extreme tolerances - even for the explosive Battlehammer, "close enough" will do, allowing a quick configuration to be at least somewhat plausible.

    Role-Playing Games 
  • In Mass Effect, ammunition is nothing more than a metal block that gets shaved into the proper form which for the sake of gameplay is as-good-as-unlimited, with rate of fire being limited by the weapon's heat sink. The block in a standard assault rifle is about 5,000 shots, which is more than enough to fight a war, and with field tools a new block can be swapped into place in a matter of minutes. In Wrex's backstory, he once fought a duel in which he ran out of ammo and had to take a gun from a merc he'd killed earlier, but only after the duel had gone on for three days.
    • Mass Effect 2 kept the unlimited ammunition, but added "thermal clips" that absorb heat from the weapon and eventually need to be discarded. Essentially, they act just like ammunition. The clips are universal - pick one up and it adds more total shots to all of your weapons. However, the game does feature a more straight example of the trope with the Heavy Weapons, which do use traditional ammo... the same ammo, whether the weapon is a rocket launcher, an experimental BFG, or an alien energy weapon built from technology beyond what anyone else has. That this "ammo" is actually a high-density power cell doesn't explain either its universal compatibility or the weapons' ability to form complicated projectiles from that raw energy - though it may be that, like standard mass effect weapons, at least the second point is rendered moot by the weapon typically having more than enough ammunition to go through a full load of energy dozens of times, and being serviced on return to the Normandy. Also, Shepard can run out of thermal clips for one weapon, yet still have plenty of shots left in the others, which is inconsistent with said ammunition being universal.
  • Fallout: New Vegas allows weapons to share ammo, with differences in damage dealt per shot by them often depending more on what type of ammo is loaded into them rather than the weapon itself; overpressure ammunition (or overcharged/max charge energy cells and microfusion cells) deal greater damage and have better armor penetration. It's not even usually a clear choice, either, as Breakable Weapons is in effect and the most common ammo that deals more damage tends to be surplus bullets that degrade your weapons faster. Likewise, there are low power versions of cartridges (like .223 for 5.56mm weapons or .38 and .44 Special for .357 and .44 Magnum, respectively) that deal less damage but cause less degradation. There are even special hand loaded, match grade rounds and bullets like wadcutters or jacketed soft points that deal extra damage and have better armor penetration without degrading the weapon, and rounds that deal better damage (hollow points) or have better penetration (AP) while doing less of the other type of damage. Simply put, there's such a huge variety of ammunition that the game had to include reloading benches to let players reload their ammo with powder, lead, and primers (either purchased from vendors or taken from broken down ammo that you don't need to use) or build their preferred loads. A major part of the modding scene for New Vegas is adding more ammunition types and expanding the reloading aspect to ensure that everyone can make whatever they want.
    • New Vegas also inverts this with shotguns for the sake of Sorting Algorithm of Weapon Effectiveness: most common, early-game shotguns use 20-gauge shells instead of 12-gauge, even though only one of the three shotguns' real life bases was available in 20-gauge.
    • With the Gun Runners' Arsenal DLC installed, the intercompatibility of ammo types makes some more sense. .223 and 5.56 NATO cartridges are just slightly different versions of the same cartridge, while weapons like That Gun and the Service Rifle are chambered for the same NATO cartridge. You can also, as in the Real Life examples below, create Overpressure cartridges that have significantly greater muzzle velocity, but damage the barrel more when fired. Some specific weapons, like the Anti-Materiel Rifle and the various 5.56 NATO guns, can even have special Match ammo made for them, which uses greater numbers of crafting ingredients to produce ammo, that in turn does less damage to the barrel and has greater accuracy, reflecting the wide variety of grades for powder and primer in real life. Esoteric ammo like Dragon's Breath rounds and Coin Shot for the 12-gauge shotguns also tend to do more damage to the barrel of the gun, for increased realism.
    • Most (though not all) small energy cell, microfusion cell, and electron charge pack-using weapons justify the universality by not strictly using the cells as ammunition — being energy weapons, the cells only provide the energy to power the attack, which makes it a great deal easier to universalize things and simplify logistics to just one of three types of ammunition. Much like ammo above, the player is also able to recycle used cells, convert one type to another, and buy or produce low-charged "bulk" cells (which reduce damage but also weapon degradation) or overcharged ones (which increase damage and degradation instead).

    Shoot 'Em Up 
  • DownWell features gunboots that can fire a variety of ammunition. This is because they run off of "charge" rather than ammo; you're reprogramming them to fire differently when you pick up a gun mod.

    Survival Horror 
  • Dino Crisis starts you out with a Glock 34 pistol in 9mm that can later be upgraded with a replacement barrel and slide to turn it into a Glock 35 in .40 S&W. Like a lot of early adopters of .40 S&W, Glocks for the cartridge were made by sticking new barrels onto the existing 9mm frames, so converting one to the other by simply replacing the barrel and slide would work in reality - although you wouldn't be able to fire 9mm and .40 interchangeably from the same barrel as you can in-game.

    Third-Person Shooter 
  • Oni has two kinds of ammunition: kinetic, which supposedly consists of explosives/propellant and slugs, usable for everything from SMGs to rocket launchers, which configure them appropriately on loading; and energy, which is for things like typical plasma blasters and tasers. The bigger the gun, the fewer shots any given ammo will provide before being used up.
  • Resident Evil:
    • Resident Evil 4 again may fall into this. Among the weapons that share ammo are the Broken Butterfly revolver and the semi-auto Killer7, both of which take .45-caliber rounds. So long as they were rimmed cartridges or at least attached to a moon clip, this would be entirely possible; revolvers will generally shoot anything you can fit into their cylinders. Also, the two scoped rifles, the Springfield M1903 and the H&K SL8, share ammo; while the Springfield in reality uses .30-06 rounds, the in-game description flat-out states this one has been rechambered for the SL8's .223 Remington. The 2023 remake goes further by adding the CQBR rifle which also uses that ammo type, befitting its real-world base also being a 5.56mm rifle.
    • Resident Evil 2 (Remake) fixes leftover issues of this nature from the original game. Claire now gets two revolvers, her first one being a Smith & Wesson Bodyguard in .38 Special that actually could, at least in theory, take 9mm Para rounds like Leon's VP70. Her second, replacing the SAA as her bonus weapon in a B scenario, is a Ruger Blackhawk, which gets its own unique ammo type (.45 ACP, which is a real chambering for the Blackhawk) that is only shared with Leon's equivalent bonus weapon, an M1911.
  • Averted in Max Payne, where the only weapons that share ammo are pump-action and sawed-off 12 gauge shotguns, which are reloaded with loose rounds. Every other ammo type is identified by the weapon it matches; even the other guns that do share ammo in real life (the 9mm Beretta 92s and M11s, or the also-12 gauge Jackhammer) use entirely different magazines. Max Payne 2 continues with this system, albeit making less sense with the shotguns.note 
  • Subverted, of all things, in Red Faction: Armageddon. Every gun takes unique ammunition and picking up a gun will only give ammo if you have a copy of that gun in your inventory. However, the vast majority of your ammunition comes from generic containers loaded with a random amount of ammo for some or all of the guns you have. These containers will only ever contain ammo for the guns in your inventory, so the game (in practice, if not in form) has a sort of universal ammunition pickup.
  • Since the weapons in Splatoon use ink rather than physical bullets, every weapon can be reloaded by just shifting into squid/octopus form and swimming through the player's ink color.

    Wide Open Sandbox 
  • Grand Theft Auto: San Andreas allows ammo to be picked up from other weapons in the same slot, and for the most part only shares ammo when it makes sense. The pistols don't share ammunition with one another, being that one fires a bigger bullet than the others, and another presumably uses lower-velocity ammo to complement its suppressor; the SMGs and shotguns can take ammo from other weapons in their class, since they do fire the same bullets as one another in real life (respectively 9mm and 12-gauge). However, the 7.62x39mm AK-47 and 5.56x45mm M4 also share ammo.

Non-video game examples

    Comic Books 
  • Rogue Trooper's Action Special that came out in the mid 1990s did a Schematized Prop for Friday's equipment. His rifle is stated to be able to vary its calibre and rifling, allowing him to fire any standard Nort or Souther round.
  • Subverted in Tex Willer: while the Colt Single Action Army was available in the same .44-40 round as the Winchester 73, Tex and his friends explicitely use the .45 Colt version, as indicated whenever they buy ammo.

    Films — Live-Action 
  • Most blasters in the Star Wars universe use a substance called tibanna gas, with separate power packs used to excite that gas into a form that makes them deadly projectiles. Apparently power packs come in a universal format too; the power packs for E-11 rifles and DH-17 pistols in particular, both being based on the same real-life weapon, are visibly identical.
    • KoTOR 2 has one quest in which you run a across a Proud Warrior Race Guy who was hiding from some predators. If you choose to mock him for managing to run out of ammo, he will ask if you have ever emptied a blaster and needed to reload (thus also hanging a lampshade on the fact that the two games have Bottomless Magazines).
      • Power packs are separate from the blaster's supply of energetic gas; an E-11 as used by the stormtroopers requires the power pack to be swapped out much like a rifle magazine every 100 shots, while the gas will last for about 1000 shots but require more detailed work and time to refill.
    • The Dark Forces Saga had one type of blaster ammo in the first game, and two in later games, both of which could be recharged from the same power stations.
  • Used incorrectly in Courage Under Fire where a key plot point was whether or not there was ammunition for the M249 SAW. At the same time, there was ammunition available for their various M16s. Both weapons take 5.56mm NATO rounds, and the version of the M249 shown in the film even has an adapter to accept M16 magazines.
  • A guide to the James Bond movie series states that Bond's favorite gun is the Walther PPK because its ammo is easily found around the world, fitting his globetrotting lifestyle. This is probably no longer canon post-reboot, when Skyfall explicitly stated that the new, high-tech PPK he'd been issued was in 9mm Short/.380 ACP rather than 7.65mm/.32 ACP, which dates back to the tail end of the 19th century and was so ubiquitous as a police and self-defence pistol calibre that it was grandfathered in behind the Iron Curtain. However, China still uses it in a limited capacity for police sidearms and .32 rounds are still fairly popular (mostly for very compact "mouse guns", usually smaller than the PPK).
  • Referenced, subverted and parodied in Iron Man 3: Tony asks for Rhodey's extra magazines, and he reminds his friend that "It's a different gun! Those aren't universal!".
  • Die Hard only gave McClane one starting magazine for his Beretta, but once he captured some of the enemy MP5 submachine guns, he also was able to top off his lone pistol mag because the two weapons share 9mm ammo. It helps that McClane had a lot of downtime during the whole ordeal, where he's presumably loading magazines off camera.
  • Logan. Wolverine carries around an adamantium bullet in case he's Driven to Suicide. Later, a revolver taken off a Reaver turns out to be exactly the right caliber to fire the round when it's needed for the final battle. This is possibly justified as the two most popular revolver calibers, thus the ones he most likely had the adamantium cast to fit, are .357 Magnum and .38 Special, which are themselves interchangeable to a certain point (both rounds are the exact same diameter, but the .357 has considerably more propellant), and the revolver he grabs is indeed a .357 one.

  • Similar to the Invisible War example above, in John Scalzi's Old Man's War, the rifles used by the Colonial forces use nanotechnology-based ammo that reconfigures itself into whatever you're asking for—including rockets, grenades, bullets, and microwaves. You can even create your own custom firing macros (eg., fire a grenade followed by a blast of flame for good measure).
  • The Doom novels note that the standard pistol and the "Sig-Cow" rifle use the same 10mm ammunition, resulting in Flynn often trading up to the rifle after his frequent losses of all his acquired weapons.
  • In the denouement of The Three Hostages Hannay fires a shot at Medina, then realises that the spare ammunition he's brought is the wrong calibre and won't fit into his rifle.

    Live Action TV 
  • Humorously averted in a scene in Burn Notice where Sam is needling Michael about having no life outside the spy business. Sam offhandedly mentions that his girlfriend Veronica once asked him if bullets came in different sizes.
  • Being forensics shows, CSI and its spin-offs and bandwagon-jumpers routinely avert the trope. In a notable example on CSI, the very fact that the rounds used in the crime were of an unusual caliber and design was a plot point. The rounds aren't even commercially available in the States. Turned out they came from a batch of FN P90s stolen from US forces in Pakistan.
  • Humorously averted in Shameless (US). Frank gets hold of an old WWII Luger and wants to shoot it in order to scare his girlfriend. However, there is no ammunition for the gun so he just grabs some random bullets that fit into the gun. When he tries to fire it, the gun blows up in his hand.
  • Averted on Elementary. A man murders his wife using a plastic gun that he made using a 3D printer. He later makes another plastic gun from the same blueprints and tries to kill his accomplice with it. However, this time he makes the mistake of using a slightly more powerful bullet and the gun blows up in his hand since the plastic cannot handle the increase in pressure.

    Tabletop Games 
  • The tabletop RPG Shadowrun suggests handling ammo this way: all weapons of the same class use the same ammo, for simplicity.
    • Then again, its Sega Genesis game fits the above Inexplicable Example table, as Ares Universal clips not only fit any gun they're loaded into (regardless of class), but round themselves off to maintain a roughly equal percentage of ammo remaining across unequal magazine sizes.
  • Played fairly straight in BattleTech. No matter where or when in the competing Successor States the weapon and ammunition were manufactured, as long as their general type matches it'll fit; AC/5 ammo will work in any AC/5 ever built, never mind that those can canonically come in different calibers. The weapons and feeding systems are even flexible enough to handle special-purpose ammunition that is canonically sufficiently heavier than normal to halve the number of shots! Yet on the other hand, the 'general type' match must be strict — no shooting standard shells from a more advanced (say, LB-X or ultra) autocannon of the same size or vice versa, no feeding missiles from an LRM-15 bin into an LRM-5 rack despite the fact that both get 120 identical missiles to the ton and feeding launchers of the same size from any matching magazine mounted somewhere on your unit is A-OK.
    • Justified when it comes to Gauss Rifle technology; since they are basically Magnetic Weapons in function, all they need (in-universe anyway) is a sufficiently aerodynamic ferrous slug of adequate weight, and as it is considered high technology, everyone's designs are based on recovered information from a more unified, more advanced era. The Clans, as descendants from the military of this same high-tech era, also drew from the same blueprints. It turns out that the Star League had proved the best results come from flinging a chunk of metal about 125kg at mach 2.
    • Battletech laser weapons are called out as using standardized power packs that have universal connectors for any and all electical equipment, although not all power packs have the energy capacity to be used on weapons.
  • Painfully averted in GURPS: High Tech which gives an exhaustive list of ammunition types. Played more straight in Ultra-Tech where there are only a dozen different rounds between all the guns. High Tech even has a table explaining ammo compatibility (including showing how less powerful and/or smaller parent cartridges fit into their descendant guns, like .38 Special into .357 Magnum, but not vice-versa), and optional rules that let the GM determine the effect of loading incompatible ammo that somehow fits in the gun (with the best result being lower efficiency and possible jamming, and the worst result being the gun exploding).
  • An odd version in the Wasteland RPG. Ammo calibers were standardized (.45, 9mm, 7.62x39mm, and energy), but the clips themselves were 'universal'—a rifle ammo clip could fit in any rifle. Their capacity was determined only by the weapon they were loaded in: the same clip that put 7 rounds in a .45 pistol gave 30 to a submachine gun.
  • KULT handles this absurdly, stating that any weapon can fire ammo of the proper caliber or smaller.
  • At least one expansion splatbook for Mutants & Masterminds / True 20 list ammo as Pistol 1-3, Longarm 1-3, and so on, with higher numbers corresponding to higher calibers. So Pistol 1 ammo fits holdout pistols (Derringers), while Pistol 3 ammo would be chambered by heavy pistols like the Desert Eagle.
  • Most Role Playing Games set in some sort of science fiction genre list only one or two types of ammo for energy weapons, usually an energy cell for 1-handed blasters and a power pack for longarms.

  • Nerf darts do fit with the majority of Nerf guns, it's when you have a non-Nerf brand gun (like Buzz Bee or Air Zone or any knockoff) that you run into problems.
    • Of course, darts come in a variety of diameters, which obviously won't fit smaller weapons. This is mostly an issue for Bows, the Titan rocket launcher, the Elite Demolisher's underbarrel grenade launcher, and blasters that use either ball ammo or the older Mega Darts.
    • Modern post-2000s blasters tend to use several common shared ammo types:
      • All N-strike and N-Strike Elite blasters that use the Clip System magazines share the common Streamline Micro Dart as well as the new Elite Streamline and Elite Suction-cup Darts.
      • All muzzle-loading blasters and a number of non-CS blasters can share the Sonic Micro/Whistler micro darts or the Suction Cup micro darts. Most of them can also share the Tagger micro darts with Dart Tag blasters.
      • Several revolver blasters, like the Maverick, Spectre, and Strongarm, are all able to use any Micro Dart due to the short dart posts in their chambers.
      • All Vortex Blasters share the XLR disc ammo.
      • Elite Blasters can all use the streamlined Elite Micro Darts, and mostly retain backwards compatibility with the older N-Strike Streamline Micro Darts. The Rebelle and Zombie Strike series blasters also use the same base ammo type. The only exceptions are the Elite MEGA blasters, all of which can use MEGA Elite Darts but not the smaller Elite Micros, some of the Rebelle bows that use unique arrows, some Zombie Strike blasters that are chambered for XLR Disc ammo, and the Elite Demolisher's underbarrel Grenade Launcher, which takes unique "Mega Dart Tech" grenades.
      • N-Strike, N-Strike Elite, Zombie Strike, Rebelle, Doomlands, Modulous, and Accu-Strike blasters that use Clip System Magazines can all swap magazines, for the most part. Yes, this means you can use your drum magazines from your old Raider with most other Clip System blasters.
      • The Rival series blasters all use the same kind of ball ammo, and the ones that have magazines all use the same form factor so you can fit a 25-ball mag into an Apollo or Zeus blaster.
    • All BOOMco (competing brand by Mattel) blasters use the same "smart dart" design, where the body is light, flexible plastic with a spongey rubber tip.
    • Some Buzz-Bee darts, especially more recent ones (2012 on) use the same diameter as official Nerf darts, allowing the ammo to be swapped between them. However, Buzz-Bee makes almost exclusively suction darts, so only Nerf blasters that can use Micro Darts (like the Maverick or Barricade) can use them. Note that they aren't entirely identical, and Nerf blasters with longer dart pegs will have shortened range.
  • Any type of squirt-gun, of course. Depending on the threading on the water tanks, some can even load soda bottles filled with water, in a pinch (thus also allowing for really prepared squirt-gunners to carry reloads).

    Web Video 
  • Mike B discusses this in the third, seventh, and thirteenth episodes of his "Stupid Gun Myths" series, talking about apparent rumors that the Soviets repeatedly designed their post-WWII guns in a way that let them use stolen NATO ammo while NATO weapons could not use stolen Soviet ammo and noting how completely impossible it would be for a gun designed for one ammo type to somehow chamber and fire a round that is wider and longer than that.
  • Played straight in Garand Thumb's "How to shoot faster (With Mojo)", where Mojo runs out of ammo for his Glock, grabs a P320 mag from Garand Thumb, and manages to fire several shots with it by holding it in place from the bottom.
    Mojo: Oh, shoot, almost outta bullets. (grabs a mag from Garand Thumb's gear)
    Garand Thumb: Hey that's not gonna work, that's a Sig mag!
    Mojo: It'll work, promise, watch. (fires five shots without issue then hands the mag back to Garand Thumb) You're welcome. (ejects the last bullet, cue everyone else collapsing into laughter)
  • Ian McCollum of Forgotten Weapons, when showing off the Q Fix scout rifle, discusses why it's so appealing for manufacturers making new cartridges to design them so that they still fit in the same magazines as their parent cartridge (in this case, 8.6mm Blackout fitting in existing .308 Winchester magazines).
    ...some people will say "sure it's easy, you just take a file and you modify the mag, and it takes like 5 minutes and then you're good to go". As far as a general market thing, that's not a viable option. You need to have magazines that just work right out of the box. Ideally magazines that are already available, readily available, that people have a lot of, that work just out of the box.

    Western Animation 
  • Fat Albert and the Cosby Kids has an episode where a kid is playing with an unloaded real gun. Eventually, the kids find a real bullet and want the kid to shoot it. However, none of the kids have any idea about calibre specifications for bullets and the gun wielding kid can barely chamber it. Before Fat Albert and the kid's father can get to him, he fires it and the gun explodes in his hand. Fortunately, the father was able to render first aid and get his son to a hospital.

    Real Life 
  • Kind of Truth in Television for armies of the world. The fewer types of ammo that you have to stock and distribute, the easier it is to supply your troops. Imagine the logistics nightmare during World War II for the U.S., when any one squad needed .30-06 (M1 Garand, M1903 Springfield, and various machine guns), .45 ACP (M1 Thompson, M3 Grease Gun, and M1911), and/or .30 carbine (M1 Carbine). Compared to today where a squad usually only needs one caliber: 5.56mm.
    • As mentioned in the opening of the page, NATO's draft standardization agreement 4179 decreed that all NATO weapons chambered for 5.56x45mm were to be designed to take the same magazines as the American M16. Note though that this agreement was never actually ratified, and a good chunk of the NATO members who do use weapons that take STANAG magazines also tend to go the extra mile and use direct derivatives of the AR-15, most commonly the Colt Canada C7 and C8 or Heckler & Koch's HK416; rarely someone will use another weapon that isn't expressly designed for them but can take them anyway, like Fabrique Nationale's FNC, which is designed to use magazines which are almost identical to STANAG ones and can be interchanged with little issue. Some NATO members like France and Germany do make STANAG-compliant versions of, or adapters for, their standard-issue weapons, but they're far more commonly used with proprietary ones.
    • One of the major reasons for the controversial U.S. Army replacement of the Colt M1911 pistol with the Beretta M9 in The '80s was so that NATO armed forces would only need to stock one type of pistol-caliber ammunition (the M1911 was chambered for .45 while pretty much everyone else was using sidearms chambered for 9mm).
    • As of 2017, the main service pistols of the world's three largest armies are chambered in 9x19mm Parabellum. America's SIG M17, China's QSZ-92-9 (5.8mm variant was not adopted), and Russia's MP-443 Grach. With the majority of both NATO and SCO armies using the 9mm, it has become the universal pistol caliber.
    • The Luger P08 had already cemented its cartridge's status as such as early as 1918, with the Bergmann MP18 submachine gun initially designed to load rounds from its famous 32-round "snail drum" magazines. The MP18 was redesigned during the interwar period to produce the MP28, which among other improvements used a simple "stick" box magazine instead of the awkward snail drum. And this magazine became basically universal for European submachine guns, with the German MP38/MP40 and the British Lancaster (a direct copy of the MP28) and Sten. Along with all the many Sten copies around the world, the 9mm version of the MAC-10, many 9mm AR-15 conversion kit, etc.note 
    • The NATO 5.56x45mm service rifle munition is based on the .223 Remington round. Though mostly the same in form factor, the NATO-standardized version has a higher chamber pressure. Some older guns that were stated to be chambered for .223 could be damaged by firing 5.56mm, but most current-manufactured civilian firearms chambered for .223 have been idiot-proofed against such damage. The inverse issue is true for the NATO 7.62x51mm battle rifle round and its parent munition in .308 Winchester - since .308 rifles are meant for hunting big game, the 7.62mm NATO round actually has a lower chamber pressure, so civilian rifles don't need any such idiot-proofing.
    • It seems like simplifying (as best they can anyway) logistical needs has been the main US doctrine since metallic cartridges became a thing. For instance, when the US Army was having trials for a semi-automatic rifle in the 1930s, the Pedersen and Garand rifles initially used a .276 caliber bullet. However, Douglas MacArthur, Army Chief of Staff at the time, rejected the round in favor of having them use the .30-06 Springfield round they already had billions of, especially after the Garand proved to be perfectly feasible when using the round (albeit holding two fewer rounds per clip than it would have in .276). Another point of this is speculation of why the US didn't adopt a weapon to counter the Soviet's "stealth" VSS Vintorez sniper rifle: the Vintorez needed custom subsonic ammunition with an effective range of 300m. To achieve that, the Soviets needed a new cartridge entirely, even if it was technically a modification of an existing one (7.62x39 necked out to take a 9mm bullet); the US didn't want to create a special purpose weapon with specific ammunition like this both for the expense of making a new cartridge in enough numbers to use its parent firearm and that this sort of thing kept failing miserably for other "specialized" items the US Army tried out.
  • Played with in real life. While ammo will work in any gun chambered for it, magazine designs are quite often incompatible. Many civilian gun manufacturers produce proprietary magazines, which would be the only magazines that could work with their firearms. Fortunately, due to the explosion of aftermarket magazines, as well as of the third-party Gun Accessories industry in general, this practice has become much less pervasive over the past 10 years, but especially since the expiration of the Clinton-era AWB in 2004. This phenomenon is partially due to the fact that gun buyers now more frequently go after a generic platform of firearm (such as Kalashnikov, AR-15, M1911, etc.), made by several different companies, rather than buy a brand-exclusive gun. Smaller gun companies also tend to make a significant portion of their profits from aftermarket magazine and parts sales, and it is cheaper for such companies to build guns which will work with common magazines for brand name guns. It's pretty much like between buying Ibuprofen or buying Motrin, but making your decision based on the container rather than the contents.
    • Ruger infamously limited its sales of magazines bigger than 5 rounds exclusively to law enforcement in the 1990s after the 1989 Cleveland Elementary School shooting. As a result, many small fortunes have been made creating third-party magazines for Ruger firearms. It should be noted that standard magazine capacity for two-handed weapons is anywhere between 10 to 30 rounds, depending on caliber, and even state laws restricting the maximum capacity of a weapon in civilian hands never limit it to less than 10. The Ruger company abandoned these restrictions in the mid-2000s after Bill Ruger died in 2002 (he had been the one to personally halt the sales of >5-round magazines) and the Bill Clinton-era Assault Weapons Ban expired in September 2004.
    • Glock magazines are particularly noteworthy for this - not only can different versions of it in one caliber exchange magazines, within reason (there's a minimum size of magazine any one Glock can take depending on frame size; a Glock 26 can take the 17-round magazines of the Glock 17, but the 17 wouldn't be able to load the shorter 10-rounders of the Glock 26), but the sheer ubiquity of the Glock (including there being versions of it, and a wide variety of magazine sizes for it, in just about every pistol cartridge currently produced) means that several modern submachine guns and pistol-caliber carbines are also designed to take Glock mags, such as the Kriss Vector and the Ruger PC Carbine. Since Glock magazines already exist for most popular pistol calibers and are known to work very well, it saves time and money on designing a weapon to just use them instead of designing your own mag. And since so many shooters already own a Glock, they'll likely appreciate a carbine that uses the same mags as their pistol. Starting in the latter half of the 2010s, a veritable cottage industry has sprung up for AR-15 variants that are designed to fire pistol calibers using Glock mags such as the Just Right Carbine, the Palmetto State Armory AR-9, and the TNW Aero Survival Rifle. One thing to note is that many pistol magazines actually do have very similar dimensions, usually with the only major difference being where the cutout for their parent weapon's magazine release to interface with them is, so in a pinch it can be possible to fire a gun with a magazine meant for a completely different gun so long as you hold it in place yourself, and cutting a new notch in the right place can let you use it properly in both guns.
    • Modern H&K pistols have similar compatibility, though only within the specific niche of H&K pistols. Basically, if a magazine fits into a VP9, then it will also fit into a P30, P2000, or USP Compact of the same caliber, and likewise magazines for the .45 version of the USP Compact work with the HK45 - however, magazines made specifically for the P2000 and USP Compact simply won't fit into the VP9 or P30 because of the shorter size (both being concealed-carry pistols with shorter grips), and it's also impossible to exchange magazines between any of these pistols and any full-size version of the USP because of the different widths (the USP magazines are too wide to even get into the other pistols, while the other magazines are too thin to lock properly into the USP).
  • The Colt Single Action Army Revolver or "Peacemaker" was available in .44-40 Winchester, which made its ammunition interchangeable with the Winchester Model 1873 lever action rifle. A useful trait in the Wild West, and what started the trend of carrying a carbine and sidearm in the same caliber so that you only had to carry a supply of one cartridge. In fact, in spite of the fame of the SAA's .45 Colt version, the .44-40 was the most popular civilian cartridge for revolvers in general in that era, for exactly that reason. A less common but still popular choice was the .38-40 Winchester, which traded slightly less power for reduced recoil and which both the Winchester 1873 rifle and the Single Action Army were also available in.
  • Fabrique Nationale's P90 Personal Defense Weapon and Five-seveN pistol share the same ammo, the 5.7x28mm cartridge, expressly designed for both guns. The AR-57 goes one step further - it is an upper receiver for AR-15 rifles that can be used to make them fire 5.7mm bullets, loading them from the exact same magazines designed for the P90 and even ejecting the same way the P90 does (dumping empties through the existing AR-15 magazine well).
    • The P90/Five-seveN is the most well-known example (and one of the few surviving ones) of the PDW fad that lasted from about 1985 to 2005, where firearm manufacturers were trying to win government and private security contracts by manufacturing submachine guns that used small, high-velocity rounds that could penetrate lighter body armor and were accompanied by a handgun chambered for the same round. Its biggest competitor, the German H&K MP7 (chambered for a 4.6x30mm round), wound up having its handgun counterpart, the H&K UCP, scrapped after nearly 5 years of delays due to poor ballistics and redundancy from the MP7 already basically being a pistol (albeit a very large one) that can be holstered on a soldier's belt and easily fired one-handed in semi-auto mode. The MP7 is a perfect example of a gun that was meant to use this trope and ended up being a near-perfect aversion of it - several other companies now make PDWs that can be special-ordered in or converted to 4.6mm, but it took close to a decade for it to happen.
    • Back on the subject of FN, their F2000 assault rifle is an inversion, not in the ammo itself but in its magazines. Its magazine well is incredibly deep, including a gasket to keep dust and dirt out when a mag is loaded. The downside to this is that magazines have to be of the same relative design as those used by the US military, i.e. flat-sided with at best inward grooves - ones with outward bulges, like a PMAG, won't fit into an F2000, unless those bulges are limited to the extremely small section of the bottom of the magazine that's outwardly visible when loaded into an F2000 (or if the dust gasket is removed, which typically isn't a good idea).
  • In general, submachine guns are issued in the service pistol caliber of the nation in question. This is usually 9x19mm Parabellum or .45 ACP, with the former as mentioned above having become the nearly universal pistol caliber worldwide.
  • Likewise, while there have been several different sizes of shotgun shell, today 12-gauge is the most common. 20-gauge and .410 bore are second- and third-place, but in this day and age, 12-gauge shotguns for specific sizes of 12-gauge shells (e.g. whether your shotgun can load shells that are three inches long or will only take ones that are two and three-quarter-inches long, and even a more recent development of shorter one and three-quarter-inches long shells for the purpose of stuffing more in the shotgun's tube) seem more common than they are. Other previously-popular shells like 10-, 16-, or 28-gauge are all but forgotten nowadays.
  • Similarly, there are different sizes of pellets for air guns, but the most common ones are 6mm for airsoft and 4.5mm for regular air guns. That said, even among these there's still room for an inability to exchange ammo; for instance, some airsoft weapons are specifically designed for lighter 0.12g pellets, while others may require 0.20g or heavier to work properly, while a .177-caliber air gun might end up shattering a plastic 4.5mm pellet just from trying to fire it. On top of that, magazines are inconsistently interchangeable - one could have two or more airsoft versions of the same pistol but be unable to exchange magazines if they're made by different companies, but then load the magazine from one into a completely different pistol made by the same company. Meanwhile, some magazines are stated as compatible but require some form of modification (like wrapping duct tape around them) to get them to fit properly.
  • One of the main advantages to the .22 Long and its variations was that a rifle fitted for one caliber could take any that had a shorter casing. This even means that weapons chambered for the long-obsolete .22 Extra Long (discontinued in 1935) can still be fired, as the still-produced .22LR will work just fine with them. A few other calibers, such as the .38 or the aforementioned 12-gauge, also do this. However, this only works with rimmed cartridges.
    • A revolver chambered for .357 Magnumnote  can safely use .38 Specialnote  or +P rounds. They're the same diameter, but the .357 case is slightly longer, so it cannot be used in a .38 weapon for safety reasons. Likewise, the .44 Magnum and .44 Special. And the .45 Long Colt and its lengthened and more powerful brothers, the .454 Casull and .460 S&W Magnum. Some modern revolvers are also sold with a second cylinder meant for an automatic pistol cartridge of the same diameter, e.g. a .357 Magnum revolver (9x33mmR) coming with a cylinder for 9x19mm. As a general rule with revolvers: if it fits in the hole, then it's OK. Automatics firing revolver rounds, however, have more factors to take into consideration, including the strength of the recoil springs - Magnum loads require stronger springs that Special loads probably won't be able to overcome to cycle properly, while Special rounds require weaker springs that would make the gun kick harder and damage itself if fired using Magnum rounds.
    • A very rare exception to this was Smith & Wesson's variation of the M1917 revolver, to supplement the M1911 pistol in World War I. Its cylinders were specifically designed for cartridges to headspace on the mouth of the casing like in an automatic so that it could take regular .45 ACP cartridges without use of a moon clip, while Colt's version of the same weapon required either a moon clip to hold .45 ACP, or a special .45 Auto Rim version of the ammo; though this in turn meant reloading S&W's version with regular .45 ammo required manually shaking the casings loose or forcing them out with a tool, since there's no rim or clip for the ejector to catch onto. S&W's more modern updates on the concept, the Models 22 and 25 and their derivatives, eschew this ability in favor of requiring moon clips, since they're easy enough to acquire in the modern day and far faster than even speedloaders, both for unloading and reloading.
    • This sort of thinking was the reason why nearly all Soviet small arms from at least 1891 to about 1951 fired 7.62mm bullets - even though they had different such cartridgesnote , if they ran critically short of barrels for anything during wartime production, they could take old Tsarist-era Mosin-Nagant rifles and recycle their barrels for use in other guns. For example, one of the old 31.5 inch barrels from the original Mosin-Nagant long rifle could be cut down into 3 PPS-43 submachine gun barrels. And early production PPSh-41 SMGs were made by taking 29 inch barrels originally intended for the M91/30 Mosin-Nagant and cutting them in half, then trimming the halves down to the proper length.
  • Some guns by design are built with frame and trigger mechanism such that by changing the barrel, chamber, bolt, and making minor modifications to the magazine system if any, can be configured to fire a different number of cartridges.
    • AK-pattern rifles, in addition to the original 7.62 and 5.45mm bullets for the AK-47/AKM and AK-74, can be modified for 9x18mm, 9x19mm, 5.56x45mm, 7.62x51mm, and even 12- and 20-gauge, among various other one-off calibers for specific military purposes. The modern AK-12, around 2013, was advertised for its adaptability, able to swap between various Russian and NATO calibers (including most of the listed ones just above) with little more than a barrel and magazine change; as of it entering production, this doesn't appear to be the case, though there are still separate variants of the weapon for different calibers as before (the AK-12 in 5.45mm, an AK-15 in 7.62mm Soviet, and an AK-19 and AK-308 for foreign customers in respectively 5.56mm and .308 Winchester).
    • One of the ways in which Heckler & Koch's UMP submachine gun was meant to be a modern upgrade to the MP5 was that it was expressly designed to be easily converted from one caliber to another (as opposed to the MP5 being chiefly a 9mm weapon, with alternate calibers requiring entirely separate variants like the MP5/10) - all that's required is a swap of the bolt, barrel, and magazine, the mags being designed to all fit into one universal magazine well.
    • The Mark XIX version of the Desert Eagle is much the same: Switch out the barrel and magazine of a .50AE version for a .357 Magnum one and you can switch ammo. You don't even need to switch the bolt assembly between .50 and .44 Magnum, because the former has the same rim diameter as .44, so the same extractor and firing pin will work. Unlike the UMP, however, since you're probably never going to use a Desert Eagle in a real gunfight, there's little point in doing so other than being tired of paying a dollar per round for .50AE.
    • Similar ideas have also fueled the creation of some more modern rounds, like the 6.5x25mm CBJ or .300 AAC Blackout, which are designed to be as compatible as possible with their parent cartridges, respectively 9mm Para and 5.56mm NATO. The new rounds are essentially the existing casings simply necked differently to take a different-diameter bullet, requiring nothing more than a barrel change to convert an existing 9mm or 5.56mm weapon to 6.5 or .300 - the actual casing is the same size, so they will still fit in the same magazines and still work with the same bolts. This goes back at least to 1994 with the design of the .357 SIG cartridge, which was based on the .40 S&W, to the point that they have the same base diameter and almost the same overall length (.357 SIG is only about a tenth of a millimeter longer), so all that's absolutely necessary to convert between the two is a barrel change - however, quick caliber conversions were not one of the design priorities, so switching a .40 S&W gun to .357 SIG may also require a stronger recoil spring to handle the .357's higher operating pressures. In turn, the .40 S&W is based off of 10mm Auto, but with a case shortened by about three and a half millimeters, about like the difference between a Magnum round and its Special counterpart - one can technically fire .40 S&W through a 10mm Auto pistol, and if it does work it can even be safer and more convenient (lower pressure generated for less wear on the gun, less recoil for a more comfortable experience - though with the caveat that it increases the risk of the gun failing to cycle - and cheaper ammo to keep it fed), but 10mm Auto through a .40 S&W gun simply won't work without more extensive modification, since the 10mm Auto won't fit in the smaller gun,note  and would probably damage the gun even if it did - keep in mind even a lot of early guns designed for .40 S&W had this issue, the cartridge becoming so popular so quickly in part because designers noticed they could stick .40 barrels onto their existing 9mm frames, without realizing those frames weren't designed for the higher pressures that .40 generates.
  • Another fact to consider is that while two guns may be chambered in the same cartridge, they may be optimized for or work better with different loads of said cartridge, due to their construction or rifling. A major part of owning a gun is determining the right load or ammo manufacturer for optimum accuracy.
    • For example, the American M16A2 and the French FAMAS F1 are both chambered in 5.56x45mm. However, the FAMAS has a 1:12 rifling twist rate, which is designed to be used with the M193 55-grain cartridge (also known by the commercial name .223 Remington), while the M16A2 has a 1:7 twist rate optimized for use with the heavier SS109/M855 62-grain cartridge; moreover, the FAMAS' operation (a stronger lever-delayed blowback system) means standard brass casings are liable to rupture when used in the weapon, requiring steel-cased rounds for the best results. The FAMAS can properly chamber and fire the newer 62-grain round, but the rifling will not stabilize it properly, resulting in poor accuracy. The G2 variant of the FAMAS has a 1:9 twist rate, which could properly stabilize both 55 and 62-grain rounds but was not widely adopted. The NATO standard SS109/M855 also has higher operating pressure than M193/.223 Remington, so it can be dangerous to fire in some rifles chambered for the earlier version. While most military rifles don't have this issue (the FAMAS for example is a very robust rifle that can handle pressures well in excess of either loading), this isn't always the case and care should be exercised in particular with civilian sporting rifles chambered for .223 Remington.
    • Some rounds are available with more powerful propellant loads, known as overpressure, +P, or +P+ loads. It is entirely possible to load up a .38 Special revolver with overloaded .38 Special ammunition that will blow the gun apart (in your hand, no less) if the particular gun is not designed to handle that propellant load. This is most common with older 9mm handguns (modern 9mm cartridges are more powerful than they had been a hundred years ago due to improved gun metallurgy) and rifles in .223 Remington or 7.62x51mm NATO, as mentioned up above (respectively, the military 5.56mm and the civilian .308 rounds have the exact same dimensions, but have a higher propellant load).
    • Likewise, some rounds are also available in reduced-velocity loads with heavier bullets, designed for reduced noise and recoil, or, in the case of subsonic loads, with suppressors. These rounds may chamber in weapons designed for the caliber, but their reduced velocity may not properly cycle an automatic action. Interestingly, the Luger P'08 gained a reputation after World War II for being unreliable among American veterans who had looted the guns during the war in part due to this sort of thing - American ammo companies produced lower-pressure rounds for the guns, ostensibly in an attempt to keep veterans from blowing up their war trophies, but just ended up making ammo that wouldn't work with the guns because the Luger absolutely requires high-pressure ammo for its toggle-lock system to reliably cycle.
    • Imperial Japan managed to pull this off with their own standard infantry weapons. The Type 38 Arisaka rifle and Type 11 light machine gun were both chambered for the Japanese 6.5x50mm round. The Type 11 also used a hopper feed using standard five-round clips. However, the Type 38's barrel was almost twice the length of the Type 11's (31 inches and 17 inches respectively), which meant the Type 11 would suffer from excessive muzzle flash and cause quite the distraction for its user. As a result, the Type 11 was issued its own specifically designed ammunition which gave less muzzle flash without sacrificing kinetic energy, complicating the supply situation. It got worse because snipers also wanted the same special cartridges to reduce muzzle flash in their Type 97 sniper rifles.
    • This was also the case, though with much less supply issues, with German 7.92mm ammo during the war. While the MG 42 and Karabiner 98k used the same ammo, just in different forms (belted versus single bullets held in stripper clips), the MG was generally issued with a slightly more powerful version to ensure more reliable feeding and extraction, something which wasn't an issue for the manually-operated Kar98. Germany also made extensive use of captured weapons, and conveniently enough many other European nations were also using 7.92mm Mausers. The use of captured rifles and machine guns that didn't use 7.92mm greatly complicated logistics, though. Whenever possible, such weapons were issued to rear-line units like military police and occupation forces in already-conquered nations, particularly in whichever nation that had originally used the weapons in question since large stockpiles of the appropriate ammo were usually still available.
  • This was extremely common in the age of smoothbore muzzle-loaders, although if calibers were markedly different it could make a difference, so during the Napoleonic Wars it was possible to shoot French 17.5mm musket balls from British "Brown Bess" muskets, but 18mm balls suited to the Bess's larger caliber could not be fired from the standard French "Charleville" musket.
    • Wellington ordered that only pistols that could fire musket balls could be used in his army. This however had an underlying reason: pistols of a smaller caliber usually were dueling pistols.
    • In the cases where a bullet wouldn't fit as-is, since it was just a bare lead ball, one could have captured enemy ammo, melted down the lead (which melts at a relatively low 327.46 °C/621.43 °F), and recast it in the appropriate caliber.
  • Intentionally subverted by the Soviets. Before and during World War II, the standard size for a medium mortar was 81mm. The Soviet Army built a medium mortar firing an 82mm round. That wasn't just cheap one-upmanship. The 82mm mortar could fire captured enemy ammunition at reduced efficiency, but if the enemy captured a supply of 82mm ammunition, it was completely useless to them unless they captured a mortar as well.
    • They did so again when they adopted the 9x18mm pistol round in the '50s, although not by intention. Under normal circumstances, a round of that diameter could theoretically be loaded into and fired from a weapon designed for the NATO standard 9x19mm. However, since the Soviets measured caliber slightly differently than NATO (by the lands in a rifled barrel, rather than the wider grooves), 9mm Makarov is 9.2mm by NATO measurements, so neither round can interchange - 9mm Makarov won't fit into a 9mm Para gun because it's too wide to fit in the chamber, while 9mm Para won't fit into a 9mm Makarov gun because it's too long for the slide to go into battery (to say nothing of the noticeably higher pressure 9mm Para reaches). Intentional or not, however, this did prevent the sorts of issues that plagued the Soviets during WWII with the earlier 7.62x25mm Tokarev cartridge - since it was physically identical to the German 7.63x25mm cartridge, only fitting more propellant in the casing, German units that had captured Soviet submachine guns were able to load 7.63mm Mauser into those guns they didn't convert to 9mm and fire them without incident, while stolen German 7.63mm guns wouldn't be able to safely fire the Tokarev cartridge.
    • The French did a similar subversion with the Chatellerault M1924/29 a few decades prior, though for the opposite reason as the Soviets. When it was first adopted in 1924, it was designed to use a 7.5x57mm round. This round was close enough in appearance to the German 7.92x57mm Mauser round that some auxiliary troops in Morocco who used captured Mauser rifles and ammo would accidentally load Mauser rounds into an M1924, with disastrous results. Starting from 1929 it was modified to use a slightly-shortened and now much more famous 7.5x54mm round so that 8mm Mauser rounds wouldn't fit into it or any future French weapons. This also led to a subversion decades later on the surplus market, since up until the 5.56mm FAMAS, all French military rifles afterward were standardized on the 7.5x54mm round: ammo for Swiss 7.5x55mm rifles is extremely common on the surplus market, and both cheaper and of considerably higher quality than the surplus French 7.5x54mm ammo (which is usually Syrian surplus, with the French Army having actually used up most of their own 7.5x54mm)... but the case is just long enough that they're not interchangeable, even though the French round is directly derived from the Swiss one.
  • The Steyr AUG assault rifle also comes in a "Para" version firing 9x19mm, including conversion kits to change 5.56mm AUGs to 9mm, and which (doubly for this trope) is designed to load from the same magazines as Steyr's earlier MPi69 submachine gun. And, as above about NATO standardization agreements, there is a version of the gun (AUG NATO) designed to load from M16 magazines, though at the cost of ambidextrous usability.
    • The IWI Tavor is similarly designed for a multitude of different calibers, with the family of rifles as of 2019 including the basic 5.56mm alongside conversion kits or dedicated variants in 9x19mm, .300 Blackout, 5.45x39mm, 5.56x30mm MINSAS, and 7.62x51mm. They are even designed to use existing magazines in the respective calibers, e.g. the 9mm versions are designed to take the same magazines as the Colt 9mm SMG - or, by extension, those of IWI's own Uzi, which the Colt SMG's mags are a near-exact copy of - since those are extremely common in several of its target markets.
  • One weird example is the Destroyer Carbine, chambered for the 9x23mm Largo pistol cartridge. This carbine was developed in Spain for police use. It was a bolt-action weapon whose action was basically that of a scaled-down Mauser 1893 rifle (not the WWI Mauser Gewehr 98 or the K98 we usually see, as the 1893 Mauser bolt cocked upon closing, whereas the G98 and K98 bolts cocked on opening) and fed by the same six- or ten-round magazines used by the Bergmann-Bayard Pistols employed by said Spanish Police units. So the average Spanish cop after 1921 was usually armed with both a pistol and a carbine chambered for the same ammo. In 1976, the Destroyer was no longer produced, having been slowly replaced by the Star Z-62, also chambered for 9x23mm Largo. Picking on cops in Spain tends to be Bullying the Dragon, as their police force has a very long history of ending political violence in the streets.
  • This is even the case for bows and arrows, which have to be precisely matched to each other's draw length, stiffness etc. if they're to be used with anything approaching accuracy. Some armies in the past used bows with extremely short draw lengths, so that their short arrows would be literally useless to the enemy.
  • Of special note is the British Sten, a submachine gun that chambered in the same 9mm Parabellum that was standard issue in the German army, since the ammo and weapons firing it were far easier to get their hands on (early battles in the African theatre netted them several thousands of 9mm rounds from surrendering Italian soldiers) than replacing the .45 Thompsons America lend-leased to them for the early stages of the war. Its magazines were even a direct copy of those of the MP 38, to facilitate using enemy ammo. Note though that despite what many have been lead to believe, there were minor differences between the MP 38 mags (and the clones made for the Sten) and the MP 40 mags that made them not interchangeable; at best, a Sten mag will technically fit into the magwell for an MP 40, but would require modification to either the gun or the magazine to hold properly.
    • Likewise, the Besa machine gun (used only in certain tanks) was left in its original 7.92x57 Mauser chambering due in part to the time and effort needed to convert it to .303, the fact that Armored Corps' supply chain was separate from the rest of the British Army and so would not be handicapped by using a nonstandard round, and the ease of using captured enemy ammunition.
    • The later Sterling submachine gun can take Sten magazines... but the Sten can't take Sterling magazines. The magazines for the Sterling are positioned just slightly further enough into the bolt's path of travel that attempting to use them with a Sten would result in the rear of the magazine being fouled by the breech block, meaning that the latter couldn't go forward. If the Sterling magazine were to be positioned in more or less the same place as a Sten magazine, the top round would now be slightly out of alignment with the breech block and so the Sten still wouldn't be able to fire. This was an intentional design choice that was made in order to force government buyers into purchasing both the Sterling magazines and the actual Sterling gun rather than simply buying the magazines only and carrying on with any Stens they might have had on hand. Interestingly, the Lanchester submachine gun (an MP 28/II clone produced by the same company that would go on to produce the Sterling gun) can be used with Sterling magazines, and magazines from the Lanchester can be used with both the Sten and the Sterling.
  • The Medusa M47 revolver inverts and exaggerates the trope by being able to take any bullet that has a diameter of 9mm or less and up to or shorter than a .357 Magnum by using special extractor fingers that clamp onto the cartridge to properly hold it in place. Though, given the fact that the extractor fingers are very fragile and that anything of a smaller diameter than 9mm won't properly grip the rifling, you'll be lucky to score a shot beyond point-blank range - in a test-fire of a Medusa on Forgotten Weapons, even an all-9x19mm load, due to the free space between the tip of a 9mm Para round in a .357 cylinder and the forcing cone of the Medusa, saw only one bullet hit close to where it was aimed, three of the others keyholing near the very edges of the target and the last two missing entirely from only ten yards away.
  • Due to the extremely similar diameter between .308 Winchester (7.62x51mm) and the 7.62x39mm Soviet round, it's rather simple to convert weapons in the former to fire the latter, such as Norinco's M305A - a rechambered version of their M14 copy - which differs from a standard M14 mostly by a slightly modified magazine release and some internal framework added into the magazine well to fit AK-pattern magazines. The existing bolt-locking mechanism even works properly with mags designed for AKs with their own bolt-hold devices (presumably in part due to that the AK's bolt is derived from that of the M1 Garand, itself a direct predecessor to the M14), though with iffy results - Ian McCollum had to push up on the bottom of a Yugoslavian magazine that worked with the bolt hold-open to ensure it fed reliably in his video on the M305A, while a Russian AK mag that didn't lock the bolt open fed perfectly.
  • The MAS-49 and MAS-49/56 have a unique kind of magazine system, where the magazine catch lever is on the magazine itself rather than part of the rifle.note  This allows owners of surplus rifles to easily convert magazines for other weapons into extended MAS-49 magazines, assuming they fit into the 49's mag well and hold the appropriate ammo (like a 25-round FM 24/29 magazine for a 7.5mm version, or a 20-round FAL magazine for one of the rare 7.62mm NATO conversions), by welding a spare catch onto them.
  • Grid-type vertical launch systems are the closest thing to this trope for naval missiles - the American Mark 41, the most common type, can fire seven different missiles and replaced no less than six different missile launchers. Unfortunately, there is no trans-national compatibility, something most clearly shown with the South Korean Navy, which on its larger ships operates the Mark 41 for American standard missiles and an indigenous K-VLS for locally built missiles.
  • Forgotten Weapons goes into detail on the many different kinds of 9mm bullets, and the compatibility and legal difficulties that can arise from this diversity of ammo types all using similar dimensions.
  • Discussed in The Chieftain's Hatch when covering the M3 Medium tank. The initial ammunition used for the 75mm cannon had reliability issues. The British Army, who was a prime user of the tank, solved the issues by using another country's ammunition of the same caliber. For the high explosive rounds, they found the French 75mm field gun's projectile had a better fuse, and since the American 75mm shell was based off of it to the point of being completely identical in layout, it was a matter of swapping the fuses. For the armor piercing round, the Brits captured several lots of projectiles made for the Panzer IV's 7.5cm main gun and they happened to fit in American shell casings with only minor modifications.
  • Downplayed with the HS Produkt VHS-2, which as of 2024 is only officially available in 5.56mm, but comes with replaceable magwells that can be swapped out to fit different magazines that take ammo of those dimensions: as standard the Croatian military uses it with a magwell to take G36 magazines (given that's what they had the most of before adopting the VHS), though they've also made ones to take STANAG mags (primarily for the Springfield Hellion, a semi-auto version sold in America, since AR-15 mags are by far the most common there) and those of the FAMAS (made for French military trials to replace that weapon). Also noteworthy is that each of these magwells is set up to still operate the same way regardless of the magazines it's compatible with: whether it's a G36 or STANAG magwell, you still remove the magazine by pressing a lever right behind the magazine.


Video Example(s):

Alternative Title(s): Universal Ammo


Why use a different bullet

Adele hands Jigen a .45 ACP bullet for his revolver, which takes .357 Magnum bullets. They don't work like that in reality.

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5 (1 votes)

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Main / UniversalAmmunition

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