Within the first few minutes of the movie as the camera follows an officer walking around the rear of the truck, an injured soldier can be seen laying on floor of the truck and has a boot protruding from under the blanket. The boot can be seen in clear view with absolutely no signs of wear to the sole which would be impossible for Germans retreating from Russia after marching and fighting all the way there.
The Lieutenant is carrying a Russian made PPSh-41 light machine gun with drum magazine (35 round capacity) throughout the movie. The Russian rifle is 7.62 caliber while German rifles were 7.92 caliber. The ammunition was not interchangeable. He is the only one of the group carrying this type of weapon and fires it frequently. Neither he nor his men are carrying spare magazines for it, and he is never seen reloading it.
He isn't seen reloading, but his is wearing a pouch on his left side that is a magazine pouch for the weapon and contains one magazine.