'Compact Special Pistol "Thunder"') is an over and under, double-barrel, derringer-type firearm designed in the Soviet Union in 1972.

[1] The firearm is chambered for the silent 7.62×38 SP-3 cartridge which can be loaded via a two-round clip.

The weapon was used operationally in Afghanistan and in Central America during the Cold War.

[2] An FMLN supplied MSP is believed to have been the weapon used to assassinate Contras leader Enrique Bermúdez.

When fired, an internal piston within the cartridge launches the bullet forward and retains all the gases within the case, thus making a near silent weapon with almost no flash.