NAME – 18.5x70mmR – 12 Gauge 2 ¾ in M257 #4 Buckshot

TYPE – Shotgun shell

YEAR OF INTRODUCTION – 1967

COUNTRY OF ORIGIN – USA

CASE TYPE – Rimmed straight

CARTRIDGE LENGTH – 6.2 cm (2.515 in)

CASING LENGTH – 7 cm (2.76 in)

CASE HEAD DIAMETER – 18.9 mm (0.744 in)

CASE RIM DIAMETER – 20.8 mm (0.819 in)

LOAD – #4 Hardened Lead Buckshot

LOAD WEIGHT – (540 grains)

PELLET DIAMETER – 6.1 mm (0.24 in)

NUMBER OF PELLETS – 27

PELLET WEIGHT – 1.3 g (20 grains)

TOTAL ROUND WEIGHT – (748 grains)

MUZZLE VELOCITY – 384 m/s (1260 fps)

NOMINAL BARREL LENGTH – 50.8 cm (20 in)

MUZZLE ENERGY – 2580 j (1903 ft/lb)

MUZZLE ENERGY PER PELLET – 95 j (70  ft/lb)