PPSh-41. Like the bastard child of a Thompson and an AK, it combines the coolness of both of them. I know the drum mag was a bit prone to jamming if you dented it, so the stick mag was better, but along with the T34 and some good old fashioned guts, it nevertheless kicked the Nazi scumbags arses from Stalingrad all the way back to Berlin, and then tore them a new one when they got there. Both the tank and the gun proving that cheap and cheerful in large numbers beats technically superior and complex in lesser numbers any day of the week.
PPSh-41_from_soviet.jpg