The show is not as good at keeping everything military-related straight.
Frank demands and receives a Purple Heart for getting an eggshell in his eye during an artillery barrage. In real life, he would have been denied as the injury wasn't directly caused by enemy action.
If the egg shell ended up injuring him as a result of the artillery attack, he would be eligible for the Purple Heart. The injury was superficial and didn't require medical attention. If it had, he would get a Purple Heart. I knew a guy who got a Purple Heart for having been hit in the head with a typewriter as a result of a mortar shell hitting when he was under his desk.
Earlier, he demanded a Purple Heart for "falling" while running to the shower (actually a back spasm from bending too far dancing with Margret), but Henry refuses to approve his application.
Actually, Frank was awarded the purple heart on that occasion. Hawkeye stole it before he could receive it to give to a marine who lied about his age to impress his girlfriend before he was sent home.
The Marine private (Walter/Wendall) would be as ineligible for the Purple Heart as Frank was. Despite having the actual medal, Walter/Wendall would have no paperwork for the medal, but Frank would, so stealing the medal and giving it to Walter/Wendall would give him possession of the medal, which may impress the girl back home, but little more.
Potter is correct in stating that the Army Good Conduct Medal is only for enlisted soldiers. He's wrong in insisting that his status as a prior-service enlisted soldier entitles him to wear the medal, which he is seen wearing from time to time and has framed on his wall. What he (or the writers) failed to realize is that the medal was awarded long after Potter was an enlisted soldier and that the retroactive dates don't go back to when he was enlisted and eligible for the award (they only go back to 27 August 1940).
As a Chaplain, Mulcahey would have entered the military as a Captain, not a Lieutenant.
Likewise, doctors were not automatically accepted as Captains. There were many instinces of surgeons with the rank of Lieutenant.
The Points system was discontinued for personnel rotation by the late '40s, and was never used for rotation of doctors.
Virtually no character wears divisional or even unit patches.
Under the Uniform Code of Military Justice, just about every character could be charged with a plethora of very serious offenses, and being a doctor would not have saved anyone. Including but not limited to:
Conduct unbecoming of an officer, which covers: knowingly making a false official statement (Frank in 'The Novacaine Mutiny"); dishonorable failure to pay a debt; cheating on an exam (Radar when taking a high school-equivilency exam); opening and reading a letter of another without authority (Radar numerous times); using insulting or defamatory language to another officer in that officer’s presence or about that officer to other military persons (Hawkeye and Trapper to Margret); being drunk and disorderly in a public place (Hawkeye, Trapper, BJ); public association with known prostitutes; committing or attempting to commit a crime involving moral turpitude; failing without good cause to support the officer’s family; and enlisted personnel gambling with commissioned officers.
Maximum punishment: Dismissal, forfeiture of all pay and allowances, and confinement for a period not in excess of that authorized for the most analogous (similar) offense for which a punishment is prescribed in the UCMJ, or, if none is prescribed, for 1 year.
Adultery (Frank, Margret, Henry, Trapper). Maximum punishment: Dishonourable discharge, forfeiture of all pay, and one year confinement.
Firearm discharge through negligence (Frank, more than once). Maximum punishment: Confinement for 3 months and forfeiture of two-thirds pay per month for 3 months.
Fraternization (Radar and the nurse he lost his virginity to, Margret and Scully). Maximum punishment: Dismissal, forfeiture of all pay and allowances, and confinement for 2 years.
Gambling with subordinate, i.e. non-commissioned officer with enlisted personnel (most of the senior NCOs). Maximum punishment: Confinement for 3 months and forfeiture of two-thirds pay per month for 3 months. In fact, gambling in and of itself is illegal, though not strictly enforced.
Opening another's mail (Radar, Frank on occasion, even Hawkeyeopens the other Captain Pierce's mail, knowing it isn't his). Maximum punishment: Dishonorable discharge, forfeiture of all pay and allowances, and confinement for 5 years.
Purjury (Frank). Maximum punishment: Dishonorable discharge, forfeiture of all pay and allowances, and confinement for 5 years.
Members of the unit take liberties with military regulations and protocol and the way military law is handled is inconsistent with reality:
Hawkeye gets away with mutinies he commits, but gets cleared of the ones he doesn't commit.
Officers often pull rank on lower enlisted soldiers, a practice that would get the officers in trouble, at times countermanding a lawful order with an unlawful order. Being of higher rank doesn't mean you can violate rules or bully people into doing what you want them to do.
When Hawkeye is on trial for evacuating a patient, General Steele goes crazy during the proceedings after asking the pilot to sing, which seems to clear Hawkeye of the charges against him.
No one wears their uniform right. You could argue that draftees don't know and don't care, but even regular Army soldiers with 10 or more years of service are regularly seen with bad haircuts, incomplete uniforms, and no regard to military protocol in the proper wear of the uniform.
For those who argue that draftees would be more likely to ignore uniform regulations and claim this is an accuracy of the time, this doesn't explain why the soldiers modify their uniforms and have haircuts and facial hair that matches the 1970s instead of the 1950s, like the show's setting.
Hawkeye violates the chain of command and always gets away with it.
The chain of command itself is too flat. The only person whose rank matters is the CO and whoever he puts in charge when he's away.
Charles nearly kills a patient when he mistakes a bottle of curare for morphine in post-op (which aside from him not verifying its contents, this raises the question of what a paralitic like curare was doing in post-op), and, a few seasons later in "Taking the Fifth", Klinger and Potter trade for curare when the Army bans its use, even mentioning the ban as recent. The US Army never approved the use of curare in Korea to begin with.
In "Bombshells", when BJ receives his Bronze Star, Potter dismisses the formation with "At Ease. Dismissed." This is illegal, as the only legal command that can be given at ease is "Attention".
At least once, Klinger tries to claim exemption from service under the Sole Survivor Policy, claiming his two brothers had died in a boiler explosion in Toledo. The Sole Survivor Policy only applies to family members killed while serving in the military, though this could be justified as Klinger was grasping at straws, since he was an only child, and admitted to it when filling out his personal information.
After Col. Potter finds out about his paid off mortgage, he thinks back to telling his wife there was housing for rent on the base. Base housing is not rented by service men or women. Base housing is a benefit for married enlisted men and officers. There are also bachelor officer quarters (BOQ).
The admistiative staff is little more than the CO and a single clerk. The administrative section of a MASH would have consisted of two Medical Service Corps officers (non-doctors), a warrant officer, a first sergeant, and numerous enlisted men ranging from master sergeant to private. Granted, in any military organization there are "go to" guys like Radar that can get stuff done that no one else can, but a unit run by the hospital commander and one company clerk would have fallen apart fairly quickly.
In Mail Call", Hawkeye says this is his second war. But then mentions that he was drafted. If he had served in WW ll he would have had a 4A classification for prior service, making him exempt.
In "OR", Trapper narrowly prevents Frank from removing a patient's kidney, saving the soldier's life since he only has one. But a man with only one kidney would have been declared 4F and would have been denied a chance to serve in the Army.
Frank's incompetence was greatly exaggerated to produce a straw man opponent for Pierce. If Frank were a fraction as bad as he was made out the CO would have no choice whatsoever in terms of reassigning Frank, preferably to an administrative position. Even if the CO dragged his foot word would get back to the combat officers who would exert pressure themselves on the matter. A true hack would be a morale killer all the way up to a battalion commander. Frank's caricature just would not stand up long term in a war situation.