The Walther MPK is a German blowback operated selective fire sub-machine-gun produced from 1963 to 1985 and chambered for the 9mm Parabellum cartridge. It takes a 32 round box magazine and has a cyclic rate of 550 rounds per minute with a muzzle velocity of 356 meters per second. The WalterMPK has a 171 mm long barrel and a folding stock. The original design had only an automatic fire rate, later models were selectable between single shot and automatic. A long barrel version was also produced as the Walther MPL with a 257 mm long barrel and a muzzle velocity of 396 meters per second. Research Walther MPK