7.7x56mmR

NAME – 7.7x56mmR

NAME (COMMON) – .303 British Mk VII

TYPE – Centerfire

YEAR OF INTRODUCTION – 1910

COUNTRY OF ORIGIN – Great Britain

CASE TYPE – Rimmed bottleneck

CARTRIDGE LENGTH – 77.5 mm (3.05 in)

CASING LENGTH – 56.1 mm (2.21 in)

CASE HEAD DIAMETER – 11.63 mm (0.458 in)

CASE RIM DIAMETER – 13.46 mm (0.530 in)

BULLET TYPE – Composite Jacketed Spitzer

BULLET DIAMETER – 7.90 mm (0.311 in)

BULLET WEIGHT – 11.34 g (175 grains)

POWDER WEIGHT – 2.40 g (37 grains)

CASING WEIGHT – 11.15 g (172 grains)

TOTAL ROUND WEIGHT – 24.88 g (384 grains)

MUZZLE VELOCITY – 744 m/s (2440 fps)

NOMINAL BARREL LENGTH – 64 cm (25.2 in)

MUZZLE ENERGY – 3137 j (2314 ft/lb)

     Adopted in 1910, prior to WWI, the Mark VII loading of the 7.7x56mmR (303 British) round was the longest serving loading of the British military. The round had an unusual composite bullet that had an aluminum (or other light material) tip inside of the bullet jacket, above the lead core. The projectile had stable ballistics, but when it struck a target, it would change its center of gravity and the projectile tended to tumble. Because it was not intended, or designed, to deform, the projectile and loading were not considered prohibited by the Geneva and Hague Conventions.

Wt of Mk 4 Stripper clip 14.13 g (218 grains)