Corrected entry: When Rambo is being interrogated by the Russian he glares at the Russian, making eye contact, not answering his questions, and eventually antagonizing him by saying f*ck you. This is not the way US Special Forces are trained. Rambo should have avoided his gaze, repeated his name, rank, and social security number. The last thing anyone who has been through SERE training (survival, evasion, resistance, escape), let alone been a pow before, would do is antagonize their captors.
Corrected entry: At the end of the film, Trautman remarks to Rambo: "You'll get second Medal of Honor for this." Congress passed a referendum in 1919 stating that nobody can receive the Medal of Honor more than once (and nobody has since World War I). Someone like Trautman would never make a mistake like that regarding military protocol.
Corrected entry: When Rambo flew the helicopter to save the other POWs, there are several scenes depicting him using the machine gun on the helicopter to shoot at the baddies. This is not possible as he was flying solo and therefore can't possibly reach the machine gun which was at the back of the helicopter.
Corrected entry: There is an American M60 on the side of a Russian chopper
Corrected entry: At the end, when Rambo goes to shoot up the headquarters, he wraps the belt around his wrist. That's a big no-no, because the belt can get caught between the rounds where it overlaps and stop feeding right, and also because the links can take off bits of skin. I found out both the hard way ;).
Corrected entry: The helicopter used by Rambo in the rescue isn't Russian. It is a normal Bell UH1D helicopter as used by the US Army during the Vietnam war. Since this helicopter was designed to fly for a max of 100 hours, it never could have been maintained or fixed until Rambo's arrival. Very strange that the Russians or Vietnamese operate with US material...