5.56x45mm SS109/M855

NAME – 5.56x45mm SS109/M855

NAME (COMMON) – SS109 (NATO), M855 (US)

TYPE – Rimless, Bottleneck, Centerfire

YEAR OF INTRODUCTION – 1964 (Original round)

COUNTRY OF ORIGIN – USA

CASE TYPE – Rimless bottleneck

CARTRIDGE LENGTH – 57.4 mm (2.260 in)

CASING LENGTH – 44.7 mm (1.76 in)

CASE HEAD DIAMETER – 9.58 mm (0.377 in)

CASE RIM DIAMETER – 9.60 mm (0.378 in)

BULLET TYPE – Full metal jacket with steel core penetrator

BULLET DIAMETER – 5.69 mm (0.224 in)

BULLET WEIGHT – 4.02 g (62 grains)

POWDER WEIGHT – 1.69 g (26.1 grains) WC 844

CASING WEIGHT – 6.35 g (98 grains)

TOTAL ROUND WEIGHT – 12.31 g (190 grains)

MUZZLE VELOCITY – 960 m/s (3150 fps)

NOMINAL BARREL LENGTH – 50.8 cm (20 in)

MUZZLE ENERGY – 1852 j (1366 ft/lb)

M27 Link – 2.07 g (32 grains)