Factual error: The final scene of the movie has Col. Kirby and the little Vietnamese boy supposedly on the beach at Da Nang, Vietnam. Kirby is saying, "The future of 'nam is you, kid", and the camera pans out to the sea and the sun is going down. The sun's sinking in the east...
Suggested correction: Nowhere in the film are we told where in Vietnam the Green Beret base is, just that it is in South Vietnam (of course). South Vietnam has a Western coast, along the Gulf of Thailand, along which anyone can watch the sun set over the sea.
Around the 18:00 - 18:30 mark a character welcomes John Wayne to Da Nang. This base is returned to throughout the film, including the infamous sun setting in the east scene. Da Nang's beaches face to the Northeast. Only when you get south of Nha Trang does the Vietnamese coast begin to offer a south to southwest horizon on the ocean.
Visible crew/equipment: During the scene where Bulldog's helicopter crashes, you can see the cable which was holding the helicopter before it dropped.
Other mistake: After one of Col. Kirby's soldiers has been killed he takes the dead soldier's M-16 and smashes it against a tree. Instead of a magazine the rifle has a plastic sound box, because the 'rifle' is really a toy made by Mattel.
Other mistake: When Kirby and the Sarge are in the helicopter during the big battle scene, when Kirby talks to Kowalski, you can see that Kirby's mouth is not matching what he says. Look closely because his hand blocks his mouth.
Revealing mistake: Except for the one that crashes, every single helicopter in this film is 100% factory fresh, brand new - no mud spatters, no scratched paint, not a dent or a blemish anywhere. They look like they just rolled off the production line. Strange that, on the front line in a war zone and all.
Factual error: When Petersen is first confronted by Col. Kirby for pilfering from his unit, Petersen neither comes to attention nor salutes Col Kirby (he should have done this as soon as he saw the Col.) This is such a huge breach of military courtesy, that one of the senior NCOs , if not Col. Kirby himself, would have called him on it instantly.
Other mistake: When Peterson is walking and gets caught in the trap, when he flies and hits the sharp needle bed, you can see clearly that the right one of them bends like rubber.
Factual error: When the Navy Lt. shows up at Camp Aavoy 29, he states that he is part of the 91st Sea Bees. However when you see him driving his bulldozer, it is marked U.S. ARMY. The Sea Bees are part of the Navy and have their own equipment.
Continuity mistake: When Sgt. Peterson is standing on top of the corrugated tin under the helicopter, his safety strap attached to the helicopter appears & disappears between shots.
Factual error: After returning to camp Savoy 29, Cpt. Nimh states that he wants to go home to Hanoi but first he wants to "kill all filthy stinking cong." The civil war in Vietnam was between the Republic of South Vietnam and the Viet Cong. North Vietnam (the capitol of which is Hanoi) was a separate country that aided the Viet Cong. So even if Cpt. Nimh killed every single "filthy stinking Cong" in South Vietnam, North Vietnam would still be communist, and he still couldn't go home.
Suggested correction: The Viet - Cong were pretty much wiped out during the TET offensive of 1968, North Vietnam won because they out - lasted the U. S and of course were supplied by PEKING and RUSSIA. Afghanistan was lost for very much the same reason, the opposition being supplied by their allies next door, and even though American service deaths had gone down to almost nothing, the U.S. bungled its departure, giving over much material.
Continuity mistake: In this scene we see Muldoon giving a talk to the press. As he empties the ammo box on the desk where the press are seated we see John Wayne and another soldier in the background standing a meter apart. We then get a close up shot of Wayne and the other soldier and they are shoulder to shoulder. In the next long shot we see they are standing a meter apart.
Continuity mistake: After kidnapping the VC Commander, at one of their rest stops, Lynn is sitting, chin down but looking up. In the scene there is a large green leaf over her left shoulder from the bushes behind her. Later they take one last rest before the choppers arrive to take them. Lynn is scene sitting on a rock in the background. John Wayne looks at her and her brother in law. The scene cuts to her again and its the same clip from the previous rest period, with the same green leaf over her shoulder, but when they cut back to a long shot she is hanging her head and there is no green foliage near her.