.303 British (7.7x57R)

The .303 British cartridge (7.7 x 56R) was originally adopted by the British Army in 1889 as a black powder round. In 1891 the propellant was switched to smokeless powder. Initially it contained a round-nosed bullet, but during the (Second) Boer War 1899-1902 was found to be sorely lacking compared to the more intermediate 7x57mm Mauser round used by the Boers. The .303 went through several developments (Marks II-VIII were the main ones) over its service history.

This cartridge remained in front line service throughout the British Empire (later the British Commonwealth) until the late 1960’s. Many surplus weapons chambered for this cartridge are still in civilian use, such as the Enfield range or P14 rifles. Commercial ammunition is still in limited production for the sake of those who own these vintage rifles.

Designation Bullet weight, g Muzzle velocity, m/s Muzzle energy, J Comments
Mk.II 14.6 640 2980 with round-nose FMJ bullet
Mk.VII 11.27 744 3120 with pointed FMJ bullet, from rifle barrel
Mk.VIII 11.27 777 3410 with pointed boat-tailed FMJ bullet, from machine gun