skorpion vz. 61
A full-auto Czech submachine gun designed in the early 60s, initially chambered in .32 ACP (7.65x17mm Browning) and later in 9mm Makarov, 9mm Parabellum and .380 ACP. Features a collapsible stock and a 10/20 round magazine.
At its introduction during the Cold War it was originally intended (an served mostly) as a compact (but potent) sidearm for tank crews and other military vehicle operators. Even today, it is in active service in the Czech military (now issued mainly to guards) and in elite police squads.
Being ultra-compact and easily concealable, as well as almost recoilless and moderately accurate up to 100m, the Skorpion is very suitable for a PDW role, and has found use by both criminals and law-enforcement units.