The German army invades Russia in 1941 and some of the the actors carry a MG42 machine gun. But this machine gun entered service in 1942 and replaced the MG34. It was only a year later, in 1943-44 that it became the most common squad support weapon.
Many variants of this machine gun were produced and are still produced and in service all around the world.
The burnt Russian tank seen in Martyukhova is a T-34-85 which was not deployed until 1943-1945 while the scene takes place in 1941 so it should have been a T-34-76. This is probably due to them being less produced.