Factual error: Then, as now, every recruit reporting to boot camp would be tested for illegal drugs, first by a urine test and then by a broad spectrum blood test in the case of a positive result. There is no reason for Elmo to try to hide his stash when the recruits are told they are to be tested - he is going to come up positive anyway. He may as well just say he has changed his mind and walk away. He is entitled to do that any time up to ten days after he signed on, and it happened a lot in real life!
Factual error: After Sergeant Hulka escapes from the Czech border crossing, he puts out a distress call on the radio that is heard by the protagonists. In it, he says he is with the "41st Armored Division, Bravo Company," which is good enough for the heroes to identify him. But divisions are divided into brigades, which are divided into battalions, which are then divided into companies, so in the "41st Armored Division" there would be literally dozens of companies (or, more likely, "troops, " since it is an armor formation) designated "Bravo."
Factual error: When the men are practicing for graduation they are using M1 rifles. The army had already switched to the M16 long before the 80s.
Factual error: The Czechoslovakian Border Guards are armed with what appears to be an Uzi submachine gun fitted with a stock. Soviet Bloc countries didn't use foreign firearms. The guards would have had Vz 58's which are visually identical to AK-47's.
Factual error: At the graduation, the MP's are wearing the National Defense Service Medal. This is authorized for active duty during times when "national emergency" has been declared during times of conflict. It was awarded for service during the Vietnam war, ending in 1974, and not awarded again until the Gulf War in 1990. To wear it, the women would have had to been in the service in 1974, which would mean they've got at least 6 years of service by the time the movie came out. On their class A uniforms, they aren't wearing any service stripes, meaning they've been in for less than 3 years.
Factual error: Stillman's aide is wearing his hat indoors. Soldiers do not wear head gear indoors unless they are armed.
Factual error: Francis "Psycho" points a knife at Winger. Weapons of any kind are absolutely prohibited in basic training. Granted he could've smuggled it in, but it most likely wouldn't make it past the shakedown part when arriving at basic. The Army and Marines prohibit weapons of any kind in basic training.
Factual error: A couple of issues with military awards as seen in the film: First, Sergeant Hulka is wearing the WWII Victory Medal, which he would not be eligible for according to his self-stated time in service (28 years, making his date of enlistment sometime in the early 1950s since the film is set in the early 1980s). Second, Captain Stillman wears the United Nations Service Medal for Korea, even though he is obviously far too young to have fought in the Korean War. (01:15:43)
Factual error: The mortar round which injures Sergeant Hulka isn't realistic. If it was a training round, its explosive would not have been sufficient to knock down the tower (based on where it lands - near the base of the tower) ; if it was an actual high explosive round, everyone within a 25-meter radius (basically all the recruits) would have been killed or seriously wounded by shrapnel.