Russian: СР-2 «Вереск» The SR-2 "Veresk" (Heather) is a Russian submachine gun designed to fire the armour-piercing 9×21mm Gyurza cartridge. It was developed in mid-1990s on the request of Russia's Federal Security Service (FSB). SR-2 differs from most submachine guns by its gas-operated action with rotating bolt, while normally SMGs utilise different blowback principles. Externally the "Veresk" is akin to the Uzi; 20 or 30-round magazines are inserted into the pistol grip.