Tags: Weapon.
The S4M (Russian: С4М) was a Soviet insurgency weapon pistol designed to be used expressly for the purpose of assassination.It was a simple break-open two-shot derringer but the unique features came from its specialized ammunition designed around a cut-down version of the 7.62mmx39 rounds used in the Soviet AK-47. The casings of the round contained a piston-like plunger between the bullet and the powder that would move forward inside the casing when fired.