In Day of Days, after the Germans with the horses are ambushed and killed, Lipton picks up an MP40 and somebody hands Winters a "Kraut rifle" as they have both lost their weapons during the jump. However they do not pick up any captured ammo, and into the next scene neither man is wearing ammo for the German weapons. Also, we don't see them check to see if the weapons are loaded. They soon come across some dead US troops and exchange their weapons for American ones, but they could not have known how long they would have needed to keep the German ones.