NAME – 4.5x39mmR SPS

TYPE – Underwater pistol cartridge

YEAR OF INTRODUCTION – 1971

COUNTRY OF ORIGIN – USSR

CASE TYPE – Rimmed bottleneck

CARTRIDGE LENGTH – 145 mm (5.71 in)

CASING LENGTH – 39.5 mm (1.56 in)

BULLET TYPE – Flat-nosed steel flechette

BULLET DIAMETER – 4.5 mm (0.177 in)

BULLET WEIGHT – 13.15 g (203 grains)

TOTAL ROUND WEIGHT – 17.5 g (270 grains)

MUZZLE VELOCITY – 250 m/s (820 fps)

MUZZLE ENERGY – 547 j (403 ft/lb)

     This is a standard-type cartridge using normal smokeless powder propellant to launch a very long flechette. The round is specially waterproofed for use underwater where it fired the flechette through a smoothbore barrel. The flechette is designed for stability and range underwater but can be used above the surface of the water in an emergency. Because of the flechette being design to be stable underwater it quickly loses stability when fired in air greatly limiting its range.