Interdynamic MP-9 Country Sweden Type Submachine gun Manufacturer Interdynamic Introduction 1983 Specifications Weight 1.7 kg (3.8 pounds) Length 328 mm stock closed, 541mm stock extended (13.25\" stock closed, 21.3\" stock extended) Barrel length 127 mm (6.8 inches) Cartridge 9x19mm Parabellum Action Blowback-operated Rate of fire 1000 rounds/min Muzzle velocity 764 m/s (2507 ft/s) Effective range 55 m Feed system 10, 20, 32, 36 and 50-round magazines

The Interdynamic MP-9 is a blowback-operated, fully-automatic 9 mm caliber machine gun. It is made of inexpensive molded polymer and stamped steel parts. 10, 20, 32, 36 and 50 round magazines are available. The MP-9 was made in two configurations, one with select fire capability and a collapsible stock, and one that is fully automatic only with no stock.

The MP-9 was originally designed by Swedish company Interdynamic AB of Stockholm as a cheap submachine gun for military applications. Interdynamic was unable to drum up any interest among governments, and the MP-9 never entered production in Sweden. Unwilling to give up on the design, Interdynamic set up a US subsidiary intended principally to market a semiautomatic version to civilians. Interdynamic USA produced a very small quantity of registered, MP-9 submachine guns (believed less than 50 total, perhaps as few as 24 in select-fire with the collapsible stock).