7.62×35 SP-3

The SP-3 special cartridge was developed by Soviet engineers for use in silent weapons during late 1960s. It features an internal two-stage telescoped piston which is located between the small powder charge and a bullet. When fired, this piston extends forward, violently pushing the bullet down the barrel and then capturing hot powder gases inside the case, resulting in virtually noiseless and flash-less discharge. It is an unique round which was used in just two firearms – the MSP pistol and NRS knife/gun, both of Soviet origin. Since it was intended primary for clandestine use, cartridge was loaded with standard FMJ bullet taken from 7.62×39 cartridge, in an attempt to confuse possible investigators.