The PM-63 RAK (Ręczny Automat Komandosów, "commandos' hand-held automatic") is a Polish open-bolt 9×18mm Makarov caliber submachine gun, designed in 1950s. The weapon was accepted into service with the People's Army of Poland and police in 1965. It has handgun-like ergonomics, a reciprocating slide instead of internal bolt which may risk hitting the shooter's eye while aiming down the sights, a bottom-folding stock, and a foldable vertical foregrip.
