Comrades in Arms: Part 2 - S6-E13
Visible crew/equipment: While Margaret and Hawkeye are hiding under the mat, just as the armed North Korean collapses to the floor the shadow of the moving boom mic is visible on the wall.
Comrades in Arms: Part 2 - S6-E13
Other mistake: During the surgery, after Hawkeye and Margaret reach the 8063rd, Margaret is explaining the procedure. She says that they are using a new vascular clamp designed at the 4077th. It appears that this is the clamp designed and built three episodes later in episode 16 "Patent 4077."
Comrades in Arms: Part 2 - S6-E13
Audio problem: When Hawkeye and Margaret are being driven into camp, everybody is cheering. Watch the driver of the jeep. He hits the horn button a number of times, but the horn is never heard.
The Merchant of Korea - S6-E14
Continuity mistake: After answering a call for help, BJ gets first a right glove on, then as he talks, gets a left glove. After the angle changes, he gets a left glove again.
The Merchant of Korea - S6-E14
Plot hole: In this episode, the military money, or scrip, is being called in and exchanged for a different color (and assumedly design - otherwise counterfeiters could just keep using their printing plates) to battle counterfeiting. However, in previous episodes several colors of scrip are being used equally and at the same time - e.g. in episode "Hey, Doc" (4-5), Sgt. Kimble collects a pot consisting of both blue and tan one-dollar scrip notes. No previous indication was given in the show that the army started a practice of using just one color at a time.
Visible crew/equipment: While in the mess tent, after Margaret's grossed out by the smell and walks away we hear Charles start playing again, and when Colonel Potter says, "Just make sure the three of you work this out fast," in this shot we can see the actor's T-mark on the floor between Potter and Hawkeye, where Margaret stood a moment ago.
Audio problem: After Potter convinces Saunders he still wants to live, the hiss from the anesthesia machine fades out even while Potter and Saunders are still standing next to it. Neither Potter nor Saunders turned off the valve again.
Revealing mistake: When Margaret whistles for the "third wave" she places Winchester's French horn on the ground, and there are three shots facing the jeep as it closes in on the horn - in the first two shots the horn's normal, but in the last shot the horn's already semi-squashed before the jeep even runs over it.
Continuity mistake: When the Jeep runs over the French horn, the crowd is a good distance back. When Potter comes out and picks up the flattened horn, the crowd is only five or six feet away without having moved up.
Continuity mistake: When BJ and Hawkeye are arguing while trying to eat, Winchester starts his French Horn. When the camera is behind BJ, he puts down his fork. When the camera cuts to a front shot of BJ, he's holding the fork he just put down. Then the camera cuts to look at Hawkeye, BJ's fork is down again.
Patent 4077 - S6-E16
Plot hole: When Hawkeye and BJ buy Margaret a new ring, it takes a typo in the inscription to give them away - which makes both of them and Mr. Shin almost clairvoyant. Not only did they somehow guess Margaret's ring size, but Mr Shin - phew, Houdini and Uri Geller together don't hold a candle to this guy - actually somehow divined the exact type and font of the inscription in the original so perfectly that Margaret actually only spotted the difference from the missing 'n.'
Patent 4077 - S6-E16
Continuity mistake: When the boys are working on the vascular clamp, Charles brings out three hard boiled eggs. After he heckles BJ and Hawkeye for a minute, BJ takes the hammer, and smashes Charles' eggs. The camera cuts to the boys, and back to Charles. There are now two eggs, and almost intact.
Visible crew/equipment: In the compound, as the camera pans to follow Potter coming toward Hawkeye, the corner of the studio is easily seen through the camo net, above the building.
Continuity mistake: In the Operating Room, as Charles hears that his phonograph has been "donated" for use during the emergency, he turns his head from left to right. In the close up, he lifts his head.
Continuity mistake: When the bomb disposal sergeant is sitting down at the end of the episode, he's facing the table. When the camera cuts in closer, his left shoulder is facing the table.
Factual error: Radar's mother's boyfriend owns a Nash Metropolitan, a car that was not produced until after the end of the Korean War.
Continuity mistake: When they are talking about taking Sophie for a walk, Roy is sitting on the bunk. His captain's bars & medical insignia are on the wrong sides. After he stands up, they are on the correct side.
Audio problem: As Roy and Loraine enter the camp, you hear a "YEE-HAW" from Roy, but if you watch his mouth, you see he really says "YAHOO."
Factual error: When Radar, Hawkeye, and BJ find the letter from cpl. Benson to I Corps, Radar says that cpl. Benson's been here since June. Later in the episode when col. Potter, Radar, Hawkeye and BJ confront Benson, Benson says he is there on orders of a colonel who did not get treated quickly enough. Potter says he remembers this colonel was there a couple of months back. BUT, this episode of M*A*S*H takes place during Kentucky Derby Day. The Kentucky Derby has always been held the first Saturday in May. So, if Benson has only been at the 4077th for two months, and he arrived in June, then this episode should be taking place in August, not May.
Continuity mistake: When BJ and Hawkeye are trying to find out who snitched on Potter, they search Charles' belongings back at The Swamp. BJ wraps Charles' white scarf around his neck. Once Charles returns to his tent, the scarf changes positions several times.
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