Crossroads - S1-E5
Corrected entry: In part 5, Crossroads, when they are firing on the Polish and the SS companies, you see the left side of the 30-cal machine gun. As it fires you see shells dropping out of the outer side. This shouldn't happen because that would indicate a disintegrating belt, but they didn't come into use until the 1960's so the rounds from the gun should be in a belt.
Correction: The machine gun has to strip a round off the belt to be fed into the chamber. The belt itself does not disintegrate, but there is no way for the gun to put the fired casing back in the belt.
Wubbman