Guns, like any machines, are prone to malfunctions; the most common, and thus the most likely to pop up in fiction, are jams and misfires. However, since there's no good reason for a gun to jam in the middle of a straightforward firefight, expect any errors to come during a crucial moment.
You can also think of it this way: does this gunshot have the power to end the plotline? If yes, and if the plot isn't at its actual end, it's fairly likely that it won't go off quite right.
Of course, when real guns jam or misfire, it's fairly easy to fix (depending on the gun and the era, of course). That said, if it comes down to timing, a misfire or jam may make or break a gunfight. It's also much more common in period pieces, as modern weapons are much more reliable than, say, 19th century revolvers.
While the title of this trope is misfire-specific, do note that it applies to any type of failure to work on the gun's part.
- In Full Metal Panic: The Second Raid, Xia Yu Lan's gun jams while she's trying to kill Kaname. She quickly and methodically clears the jam and resumes firing, averting some other tropes associated with gun jams, but the momentary reprieve saves Kaname's life.
- In Le Tueur, the killer's gun misfires right as he's about to kill himself with it. Of course, once he's fixed it, the suicidal urges have evidently passed.
- In Knights of the Dinner Table, Bob accuses Brian who is GMing of doing this to save BA's and Sarah's characters when Bob's character's gun misfires during a gunfight in a Cattlepunk game. Brian points out that the character's gun is a cheap revolver that's just been submerged in a horse trough.
- Tintin's life is saved by this several times, including one with a cannon.
- In the Gate fanfic Here We Go Again!, the titular tank engages the flame dragon and manages to wound it. The killing blow is denied when the tank encounters a bad shell and the crew has no time to remedy the issue before the dragon mounts their vehicle, damaging it as well as knocking the crew senseless. Luckily, Itami's squad comes to their rescue in the nick of time.
- In 6 Days, one S.A.S soldier tries to fire his sub-machine gun at a terrorist trying to set the Iranian Embassy on fire, but his MP5 suddenly jams. The terrorist fires his own gun and misses, but the S.A.S soldier resorts to whipping out his sidearm and returns the favor.
- Aversion: in The Way of the Gun, Longbaugh's shot gun jams in the middle of the shootout. Instead of editing around it Benecio del Toro clears the jam and keeps firing.
- In Back to the Future, Marty is saved repeatedly from being shot by Libyans because their rifles keep jamming. They are shooting AK-47s, which, in Real Life are famed for their reliability even under the harshest conditions.
- This is kind of an apple to oranges comparison. AK's are famed for their ability to continue to operate even when their owner/user shows complete disregard for maintaining the weapon such as cleaning and lubrication. Common jams such as stovepipes, and double-feeds (the latter of which is usually the result of a defective or worn-out magazine regardless of the rifle's design) are at least as common in an AK as other conventional automatics. Some would even argue the former is more common in the design.
- It's also possible that the guns are fine, and the frequent jams are from poor-quality ammunition, not implausible since they probably bought both the weapons and ammo as black market surplus of unknown age or manufacture. It may also be a joke on Gaddafi-era Libya, a country whose military was almost entirely equipped with 1960's-era Soviet hand-me-downs of very variable quality.
- Michael J. Fox gives us another example with The Hard Way, when his character fails to get shot point blank.
Nick: Heh. Guess he ran out of bullets.
Moss: Nope. [cocks gun, fires into newsstand] Misfire.
- During the Mexican Standoff in Pirates of the Caribbean: At World's End, it turns out that none of the guns work because they all got wet, thus conveniently avoiding having to kill off four main characters at once.
- Unforgiven. William Munny enters the saloon where Little Bill Daggett and his deputies are celebrating the death of Ned Logan. He confronts Little Bill and prepares to kill him for torturing Ned Logan to death.
Little Bill: All right, gentlemen. He's got one barrel left. When he fires that, take out your pistols and shoot him down like the mangy scoundrel he is.
Munny: [Points shotgun at Little Bill and pulls the trigger] Click.
Little Bill: Misfire! Kill the son of a bitch! [Gunfight begins]
- Justified as before the scene Munny was out in the pouring rain for an extended period. Older firearms cartridges were much more easily ruined by exposure to water than modern day ammunition. This is especially true of then-era shotgun shells due to the nature of its design versus a rifle or pistol cartridge.
- Averted in Get Shorty. Ronnie is not intimidated when Bones points a gun at him because he states the model is notorious for always jamming at the wrong times. Bones promptly shoots him four times rapidly.
- Man on Fire features this when the main character attempts suicide, but the gun misfires. He takes it as a sign and gives up on the idea.
- The Mexican revolves around this.
- A scene in Schindler's List in which a Nazi officer attempts to execute Itzhak Stern, but his pistol misfires. He calls over another soldier to execute Stern as the terrified man tries to explain himself, but that pistol misfires as well. The officer then pistol-whips Stern in frustration and stalks off, leaving him alive. Due to the nature of the story, this was probably based on a real incident.
- In Two Hands, Pando fails to execute Jimmy because the mook the gun belongs to put it through the wash. Jimmy manages to escape while Pando goes to get another gun.
- Operation Daybreak. An SOE assassin steps out in front of the car carrying Reinhard Heydrich and pulls the trigger on his Sten submachine gun, only for it to jam. This scene was Truth in Television; Heydrich would have survived if his driver had sped off, but instead the driver pursued the gunman who'd thrown down the Sten and fled, leaving Heydrich to be fatally wounded by a bomb thrown by a second SOE agent. Apparently the jam was caused by the weapon being packed in straw, which got into the weapon (not that the Sten gun was particularly reliable anyway).
- The Sicilian. A carabinieri corporal draws a hidden gun and tries to shoot Salvatore Guiliano, but it misfires. Guiliano then ejects the faulty cartridge and fires the pistol into the roof. This is regarded as a miracle by his followers, and the corporal joins his band. This becomes Dramatic Irony when Guiliano tries to assassinate boss-of-bosses Don Croce Malo, only for his pistol to misfire too.
- In The Dark Knight, District Attorney Harvey Dent is questioning a mafia witness who starts changing his story on the stand. When Dent approaches him, the goon pulls out a hidden gun and it misfires in Harvey's face, leading to the page quote.
- This is a recurring trope in the Mad Max film series.
- In Frankenstein Island, the machine gun Curtis has been using to destroy the zombies (and would have been able to end the final fight with a single burst) jams just as the Frankenstein Monster and the guard zombies smash through the door into the lab.
- How to Rob a Bank: When Jason accidentally barges into the middle of the Bank Robbery, Roger jams his gun in Jason's face and pulls the trigger, only for the gun to jam. This becomes a Running Gag, and Roger is constantly disassembling and reassembling his gun over the course of the movie as he tries to work out why it keeps jamming.
- During the showdown in Gunless, Jack's gun fails to fire, thereby thwarting Sean's attempt to commit suicide by gunfight. Entirely justified as Sean and Jack discuss what has gone wrong: it was already finicky due to conversion from percussion caps to cartridges; it had been severely damaged; and has undergone a rushed repair job.
- Author J.T. Edson disliked it when guns jammed or misfired for no reason in movies, so whenever it happened in his novels he would give a detailed explanation of what caused the gun to jam. That said, it still happened several times when it was convenient for his heroes. The short story Jubal Branch's Lucky B.A.R. was one example.
- Harry Potter and the Chamber of Secrets plays with this at the beginning of the climax with Ron's wand of all things. Professor Lockhart tries to use Ron's wand to wipe Ron & Harry's memories, completely unaware that the wand is damaged. It backfires, and wipes his memories instead.
- In Les Misérables, policeman Javert is standing facing Thenardier, who is holding a gun. Javert tells him not to shoot, since the gun will misfire. Thenardier shoots at point blank range and the gun, predictably, doesn't go off.
- In the climactic battle of Sheep's Clothing, Doc is emptying his repeating rifle into master vampire Alexandre Russeau and generally keeping him from rallying any meaningful counterattack—until Doc's gun jams. His moment of inattention allows Russeau to recover and close the distance, nearly killing Doc.
- Jack Ryan is able to prevent the assassination of the Prince of Wales in Patriot Games, as the ULA terrorist has a jammed AK-47. Instead, Ryan and the terrorist shoot at each other with pistols, Ryan kills the terrorist, the terrorist only manages to shoot him in the shoulder. Discussed later, in that the terrorist had taped the magazines end-to-end, which made a jam upon switching the magazines more likely.
- Young Sherlock Holmes: When Sherlock attempts to shoot Gilfilian in Red Leech, the rifle jams. Justified as the two of them had been wrestling for control of the gun on a muddy riverbank, and Gilfilian comments that the rifle has a delicate mechanism and is susceptible to grit.
- The Sicilian: When police officer Corporal Canio Silvestro fires his pistol directly at the Robin Hood style bandit Salvatore Guiliano's head, it jams. The incident helps cement Guilaino's reputation and Guiliano takes it as proof of the righteousness of his cause and spares Silvestro.
- In CSI: Miami, Speedle's nearly killed when his weapon jams from lack of cleaning. He doesn't learn his lesson and gets Killed Off For Real when it jams again.
- In Prison Break, a Defector from Decadence has his gun jam on him when he tries to blow his brains out. He tells his sister that the only other time that ever happened was in his army training. Ironically, his Drill Sergeant told him that if that ever happened for real, he'd be dead.
- In Black Sails a drunk Charles Vane is accosted by some men he has previously wronged. One of them pulls out a pistol an shoots Vane point blank in the head. The pistol misfires. Vane does not give him a chance to try again and beats the would-be-shooter to death with his bare hands. The series takes place in the early 1700s so it is not unusual for a flintlock pistol to misfire.
- In Fargo Lester sets a trap for Lorne. Lester's first shot misses and the second misfires. He is able to clear the gun quickly but it is just enough time for Lorne to get away. It was a high quality gun but it was stored in a basement for most of a year so the misfire could have been caused by any number of things.
- NCIS: New Orleans: In "Second Line", LaSalle is saved from getting shot when a crook accidentally squeezes the trigger and the gun dry fires. It seems the crook had neglected to chamber a round.
- Endeavour: The episode "Prey". When hunting an escaped maneating tiger (It Makes Sense in Context) Lord Mortmaigne suffers a repeated misfire with his shotgun as the tiger steadily advances on him down the narrow corridor of the maze.
- Daredevil (2015): In "Rabbit in a Snowstorm", John Healy goes to a bowling alley for a hit. After taking out his target's bodyguards, he pulls a gun on the target. As he raises the gun, the show cuts to the previous day, when he bought the gun from Turk Barrett, who assures him that the gun will not jam. Cut back to the hit-in-progress, and of course, the gun jams, turning the hit into a savage brawl that culminates in Healy having to bash his target's head in with a bowling ball.
- Call of Duty: Black Ops, in the Khe Sanh mission, has Woods almost getting killed but for the player's intervention when his gun jams right before he kills an NVA soldier. He tries fixing it by whacking it a few times.
- Also, in the multiplayer, to prevent people from using modded controllers, the semiautomatic rifles will jam if fired too fast.
- Mafia: Sergio Morello is one lucky bastard. The third assassination attempt on him has the Tommy Gun jam when Paulie tries to gun down the target in front of the Rainbow Garden Restaurant.
- The episode "Harlequinade" of Batman: The Animated Series originally ended with one of these, where Harley Quinn has a machine gun pointed at the Joker (because she was pissed that he was willing to let their pets die in his latest scheme). Joker makes it clear that he doubts she has the guts to shoot him, but she does... only for a flag reading "RAT TAT TAT" to pop out, to her surprise. According to the commentary, originally there was simply going to be a click, but the flag was added to soften the blow.
- President Andrew Jackson survived an assassination attempt when both of the would-be assassin's pistols misfired, after which Jackson beat his assailant half to death with his cane. Interestingly, both pistols were examined and determined to be in working order. Guess the bullets were just scared of Jackson.
- As noted above, during the attempted assassination of Reinhard Heydrich, the gun jammed, the other culprit being the vegetation that the agent had been gathering in the pocket with the gun. Why all of the greens in his pocket? To feed his pet rabbit.