Character mistake: In the showdown scene between the Vietnamese officer and Rambo, the Vietnamese officer empties an entire magazine at Rambo from only about 20 metres away but only manages to hit the ground around Rambo's feet. What was he doing, aiming at his feet? He deserved to get blown up to bits for that effort.
Factual error: The Russian Hind helicopter is in fact a French-built Aerospatiale Super Puma with attached wings.
Continuity mistake: When Rambo fires the rocket launcher at the Russian Hind helicopter, he is clearly seen aiming a LAW rocket launcher. The LAW is fired by pressing a lever on the top. But when Rambo fires, a quick edit from a previous shot (on the patrol boat) shows him pulling a trigger from the Russian RPG launcher he used to dispatch the Vietnamese patrolboat earlier in the film. The film returns to show him holding the LAW rocket launcher again.
Continuity mistake: In the end of the film after Rambo blows up the Russian helicopter, there is a hole in the front window through which Rambo shoots the rocket. In the next few scenes we see Rambo's helicopter and the hole in the window is gone, then it's back again, then it's gone, then it's back again when he lands.
Continuity mistake: During the helicopter chase scene, the mini-gun and the manual m-60 on Rambo's chopper change sides.
Continuity mistake: When the Russian is shooting from the helicopter at Rambo in the water, the rocket pods are missing from the helicopter, but after Rambo gets in the helicopter and takes over, they are back.
Continuity mistake: When Rambo leaves the village after blowing stuff up with the explosive arrows, he has about 15-20 arrows in his quiver, but when he kills the Vietnamese soldier, he only has one.
Continuity mistake: When Rambo is introduced to Murdoch, Murdoch asks for a drink and the man gets 1 from the drink machine, no other can drops down and no other shelves are full. Yet he brings 2 cans over.
Factual error: When Rambo plays possum then suddenly takes out the Russian officer's Hind Helicopter he uses an M72A2 light anti-tank weapon (LAW). When fired, the M72A2 has a back blast that can kill out to 100 feet, which means he would have either blown up his own helicopter or killed all the MIA's he had rescued...
Factual error: When the close up of the engine for the plane to drop Rambo off is shown starting up, in the next shot a voice can be heard saying "APU start". The APU starts the engine, so the engine couldn't have been started first.
Factual error: Near the beginning of the film, the airplane that will fly Rambo into the jungle is being refueled and prepared for takeoff. Ericson shines his flashlight into one of the jet exhaust ports to inspect it, an impossible task since the jet engines have already been started. Not even Rambo would be able to stand behind a jet exhaust without getting blown over or burnt to a crisp.
Revealing mistake: In a scene towards the end, we see a crowd of Vietnamese on a riverbank firing their machine guns into the trees...one soldier clearly walks directly in front of another soldier who continues firing away without hitting him.
Factual error: The big red "trigger" switch that Rambo uses to fire the rockets on the Huey is the radio/intercom switch.
Continuity mistake: When Rambo is attacking the POW camp, the Gatling gun on his helicopter is firing (spinning) in one shot, not in the next, then back and forth, yet it never stops making firing sounds or killing people.
Continuity mistake: When Rambo has rescued his first POW and running to escape to meet his check point, he is followed by the Vietnamese soldiers who chase him knee deep through a muddy swamp. The film scene then shows Rambo, seconds later, still running with the POW, but then returns to the Vietnamese soldiers who now have wet but very clean trousers.
Revealing mistake: While Rambo is flying the helicopter with the POW's you can clearly see the smoke shooting from a small metal thing below the gun.
Revealing mistake: Towards the end of the movie, when Rambo is setting everything afire with his exploding arrows, an enemy soldier stumbles through a patch of tall burning grass. As he falls to the ground covered in flames, the fireproof mittens the stuntman is wearing are visible.
Factual error: It is completely implausible that Rambo, an experienced green beret would be careless enough to get his gear caught in the plane while jumping out. Also even if he had gotten got, soldiers carry their gear in different layers that are quickly releasable via strap or clip just in case they do get stuck. Rambo would not have gotten stuck, and if he did he could detached his his gear easily and without all the drama.