Other mistake: After Klinger gives the long johns to Mulcahy, he "disappears." But if you look closely through the camo net, you can see him in the shadows of the background.
The Late Captain Pierce - S4-E4
Other mistake: When Digger shows Hawkeye the copy of the death certificate, Hawkeye steps out of the shower stall and its door swings back and forth. As Hawkeye wipes his face with the towel, we can see the top of the flesh colored covering Hawkeye is wearing. (00:08:05)
Good-Bye Radar: Part 2 - S8-E5
Other mistake: As the camera cuts to Hawkeye and Margaret working, the man behind her is holding a chest X-ray, but it's upside down, which would be useless as a guide.
Hot Lips and Empty Arms - S2-E14
Other mistake: While trying to sober Margaret up, you can see Trapper's clothing wet in spots where she hung on to him in previous takes.
Other mistake: It's 1952 when Potter arrives at the 4077. He tells Radar that he joined the army during WWI when he was 15 (he lied about his age). That would mean that Potter was 50 when he arrives. But he said that he'd be retiring in 18 months. Also, in the episode "Point of View" Potter states that this was the first time in 37 years that he missed calling Mildred for their anniversary. That would mean that Potter was 13 when he got married.
Other mistake: When the Colonel Griswald of the 1st Cavalry goes to leave camp, the Jeep he gets in is marked "4077 MASH" on the bumper instead of 1st Cav.
Other mistake: Frank Burns states when he is talking to a patient who just got a purple heart, that he would like to get a purple heart, but in the earlier episode ‘The Kids', Frank Burns received a purple heart due to a injury, and in the S1 episode ‘Sometimes You Hear the Bullet', Frank Burns gets another Purple Heart. Despite them both being stolen, they still count on his army record.
Other mistake: When Hawkeye finds the New York Times Crossword he says, "1 down, four letters..." and "1 across...four letters..." and BJ's answers are "chap" and "cast" but in the shot of the newspaper puzzle we see that both "1 down" and "1 across" are actually five letters each, not four.
Other mistake: When Hawkeye and Trapper are arguing with Henry about not sending the little boy to the orphanage, Henry says, "Look, you think I wanna send this little fella away? I got two kids of my own. I'm a former child myself," but at the end of season 1 Henry's wife delivered a boy, whom Henry was aching to be with, so Henry really has three kids.
Other mistake: While the dentist is working in Henry's mouth Frank's describing Hawkeye and Trapper's pranks, and right after we see a shot of the dog licking hamburger from Frank's ear, when it cuts to Henry saying, "Frank, just leave my married life out of this. Doc, will you watch it before I swallow your watch!" keep your eyes on Larry Linville as he mouths McLean Stevenson's lines along with him.
Other mistake: When Hawkeye walks into the shower tent while Ugly John's showering he removes his robe, and just as Hawkeye swings open the door to step into the shower stall we can see that he's wearing something, presumably a swimsuit.
Love Story - S1-E14
Other mistake: After Hawkeye asks, "Radar who?" while he's kissing a nurse, it cuts to Trapper, Radar, and Hawkeye walking past a jeep parked in front of the mess tent, then another jeep shows up with Lieutenant Anderson, but both jeeps have the same stain (looks like rust) on the front bar - the same jeep was used in both shots.
Henry, Please Come Home - S1-E9
Other mistake: While Radar's in post-op waiting for Henry's arrival he's seen reading Marvel Comics "Captain Savage and His Battlefield Raiders!" issue #10, published January 1969. It's one of the 19 issues in this comic book series which were originally named "Captain Savage and His Leatherneck Raiders," and it ran from 1968 until 1970, many years after the Korean War ended. This comic is also seen in the episode "Tuttle" later this season.
Other mistake: At the end, after General Barker tells Henry that he should give Frank a high colonic and send him on a 10 mile hike, Klinger shows up in front of them supposedly naked, but we can see the top of whatever the actor's really wearing.
Other mistake: After pulling out of the camp to head for the cave, The Bus is shown from several angles. Even though it's loaded, the shots of it travelling are re-used shots from an earlier episode, and the place it stops is a re-used shot from the episode "Rainbow Bridge"
Goodbye, Farewell, and Amen - S11-E16
Other mistake: After Klinger announces on the PA the camp's orders to Bug Out, more than a dozen of the following shots we see of the camp packing up are from the season 6 episode "Bug Out." (01:05:40)
April Fools - S8-E25
Other mistake: When Charles, BJ and Hawkeye steal Margret's tent, what's left is a frame of wood, including roof beams. From other episodes we know that the tents are held up by a wooden frame around the edges and a center pole. We even know for a fact that Margret's tent is built that way, because in an earlier episode Hawkeye and Trapper saw through the center pole of Margret's tent. We also know that the construction principle of the tents hasn't fundamentally changed since then, because when Hawkeye finds the oatmeal in his boot earlier in the same episode, you can see the center pole of the Swamp.
The Sniper - S2-E10
Other mistake: When Hawkeye and Trapper make Frank up to look like MacArthur, as they put the pipe in the "sleeping" Frank's mouth, he opens a bit wider, and bites down on the stem, then says his last line of the episode.
Dear Sigmund - S5-E7
Other mistake: As the ambulance takes off rounding a corner, the back brightens as stage reflectors or lighting rigs shine on it.
Other mistake: The Chinese patient cut the strap of Klinger's red gown, but Radar says Klinger requests a replacement brassier. Later Klinger's red gown shows no damage, although he could have retied the strap.
Answer: Even an Army field hospital would have SOME weapons for self-defense if the enemy attacked. What's meant is that it's not a combat outfit, and therefore wouldn't have enough weapons to actually attack anyone. (It's also mentioned a few times that the Officer of the Watch is supposed to carry a pistol at all times, but Hawkeye refuses to do it when he's in charge and Colonels Blake and Potter don't enforce the rule).
Captain Defenestrator