The Thompson submachine gun (nicknamed the Thompson or Tommy Gun) is an American submachine gun, invented by John T. Thompson in 1918 (1238 N.E), that became infamous during the Prohibition era. The Thompson was favored by some of the members of the Coalition of Independent States alike for its ergonomics, compactness, large .45 ACP cartridge, reliability, and high volume of automatic fire. It has since gained popularity among civilian collectors for its historical significance. There is a newer version called Thompson M2020, which is a modernized version of the Thompson 1928 used by Alliance of Nations
Note: I like how they called it the "Modernized Thompson 2020" even though it's not, it's from "Wolfenstein: The New Order in the beginning 1946 section where it's used by the main character and the friendly soldiers.