Russian silent MSP manual | Forgotten Weapons 'This is the manual of Russian MSP pistol (Malogbaritniy Spetsialniy Pistolet Small Size Special Pistol). Its something like a 2 barreled (over and under) derringer. The advantage of this gun is its special ammunition. Cartridge case has a piston behind the bullet, which pushes the bullet and seals the gases inside the case! So the shot is noiseless and no flash is generated from the muzzle. Its caliber is 7.62mm (.30cal) , muzzle velocity is 150meters per second (490 ft/s), weights about a pound.' interesting...anyone know if this was ever used in the field?