The rimmed, gentle bottleneck case shape of the .303 British cartridge shows its age, as it was intended for use with black powder and Cordite smokeless powder, but the .303 served the British Commonwealth well through two world wars. It remains a popular, capable, world-wide hunting cartridge.

Typical .303 British factory loads in the U.S. offer a 150 grain spitzer bullet at a muzzle velocity (MV) of 2,685-2,723 fps and muzzle energy (ME) of 2,401-2,470 ft. lbs. For large game there is a 180 grain RN bullet at a MV of 2,460-2,590 fps and a ME of 2,418-2,680 ft. lbs.

A reloader can do quite well with a sturdy .303 rifle. Bullets from 123 to 215 grains are available, with the 150, 174, and 180 grain weights being the most popular for big game hunting. I always favored the 150 grain bullet for hunting CXP2 class game when I owned a .303 rifle.

Given the British cartridge's capacity and pressure limit, medium burning powders such as H335, H414, IMR 4895, IMR 4320, RL-15, and W760 are appropriate.

Because of the rear locking Lee-Enfield (SMLE) bolt action of most .303 British rifles, which allows more case stretch than front locking actions, it is a good idea to just neck size .303 brass. This will extend the case life considerably, a point that is emphasized in the sixth edition of the Hornady Handbook of Cartridge Reloading.

Here are some .303 British specifications of interest to reloaders: bullet diameter .311-.312", maximum COL 3.075", maximum case length 2.222", SAAMI MAP 45,000 cup.

The sixth edition of the Hornady Handbook of Cartridge Reloading shows that 35.3 grains of RL-15 powder will drive their 150 grain spire point bullet at a MV of 2200 fps. A maximum charge of 43.9 grains of RL-15 powder will drive the same bullet to a MV of 2700 fps.

For use on heavier game, the Hornady Handbook shows that their 174 grain bullets can be driven to a MV of 2000 fps by 33.3 grains of RL-15, and to a MV of 2400 fps by a maximum charge of 40.0 grains of RL-15. These loads were developed in the 25.25" barrel of an Enfield #4 Mark 2 rifle, and used Hornady brass and Winchester WLR primers.

Note: A full length article about the .303 British can be found on the Rifle Cartridge Page.