Other mistake: In the final battle where the two rangers are waiting for Upham to bring them 30cal ammo, they fire their rifles through a hole in the wall. At one point two German soldiers are seen dying from the same shot, even though they are at least five meters (about sixteen feet) apart.
Other mistake: When the squad is walking in the field with Mellish singing, they see a halftrack and take cover. Once the halftrack gets shot at by the bazooka, Miller moves to the side of the halftrack shooting the fleeing soldiers. After that, he reloads his Thompson. Then, at the beginning of the last battle, Miller reloads his Thompson for the second time. There is no explanation why he would throw away what is considered a perfectly good cartridge.