NAME – 8×21 mm

NAME (COMMON) – 8mm Nambu

TYPE – Bottlenecked centerfire

YEAR OF INTRODUCTION – 1904

COUNTRY OF ORIGIN – Japan

CASE TYPE – Rimless bottleneck

CARTRIDGE LENGTH – 3.18 cm (1.25 in)

CASING LENGTH – 21.8 mm (0.86 in)

CASE HEAD DIAMETER – 10.36 mm (0.408 in)

CASE RIM DIAMETER – 10.49 mm (0.413 in)

BULLET TYPE – Full jacketed ball

BULLET DIAMETER – 8.13 mm (0.320 in)

BULLET WEIGHT – 7 g (107 gr)

POWDER WEIGHT – 0.3 g (4.7 grains)

CASING WEIGHT – 4.26 g (65.8 grains)

TOTAL ROUND WEIGHT – 11.5 g (177.5 grains)

MUZZLE VELOCITY – 290 m/s (950 fps)

NOMINAL BARREL LENGTH – 12.1 cm (4.76 in)

MUZZLE ENERGY – 291 j (214 ft/lb)

     This was the official Japanese military handgun round. Only three handgun designs as well as a single submachinegun series, were chambered for it. Though a few countries outside of japan used the round after World War II, it was only because of the availability of stocks of surrendered Japanese weapons.