4.5x40R SPS underwater

This unique ammunition was developed in USSR in the late sixties for combat divers. Development took place at the State Technical Institute of Precision Machine Building (TSNII TochMash), and this cartridge is used in only one weapon, unique to this cartridge, the SPP-1 underwater pistol. The SPS cartridge has a bottlenecked, rimmed brass case. The long projectile is made from mild steel, with a pointed tip. To insulate the cartridge from salt water, the primer pocket and case mouth are protected with special sealing; the bullet is covered by protective lacquer coating of dark green color. When fired in water, the bullet is stabilized by drag forces. When fired in air, bullet is not stabilized at all, and tumbles in its trajectory.



Bullet weight, g

Muzzle velocity, m/s

Muzzle energy, J






Steel bullet