In World War II, American GIs had the Tommy gun, the Nazis their MP-40s and Ivan, well, he had the PPSh-41, aka the Shpagin machine pistol.
The Soviet military churned these inexpensive subguns out by the millions and used them to help drive the Nazis off their turf and win the war.
The PPSh-41 is a crude weapon, but reliable and it is still in service today. It operates on an open-bolt blowback action and fires the 7.62x25mm Tokarev pistol cartridge.
Here's what one looks like in the hands of a goofy, and profane, "professional Russian."