303 British

7.7 x 53mm Rimmed

Introduced in 1888 the original British Military loading was a charge of compressed black powder and a 215 grain round nose cupronickel bullet.

In 1892, cordite was substituted for black powder. Cordite is a double based propellent composed of nitrocelluse, petroleum jelly and a substantial percentage of nitroglycerine . The British form of cordite had the appearance of strands of thin spagetti. Strands of this propellent were inserted into unformed and primed brass straight wall cases. The bottle neck was formed around the propellent and the bullet was then seated.

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Reloading 303 British

303 British Dimensions
Bullet Diameter (inches) 0.311
Max Cartridge Length (inches) 3.05
Max Case Length (inches) 2.22
Case Trim Length (inches) 2.12

303 British Cases and Case Life

This cartridge headspaces on the rim which allowed the designers to include a fair amount of slop between the shoulder area of the case and the wall of the chamber. This was done to ensure that dirty or corroded rounds would still chamber. Upon firing the brass case expands to fill the chamber pushing the shoulder of the cartridge case forward about 1/16th of an inch.
What this means to someone reloading for 303 British is that when these cartridge cases are full length resized repeatedly, the metal on the shoulder is worked severely resulting in a short case life.

When 303 British cases are to be fired in the same rifle then the ideal way to extract the most life possible out of the brass is to only size the neck of the case using a neck sizing die. As I have don't have a neck sizing die for 303 British, I have found that it is possible accomplish the same thing by partial length resizing using a full length resizing die. Since the 303 british cartridge uses such a strongly tapered case, backing out the sizing die a couple of turns or about 1/8 inch will size the case neck without setting the shoulder back provided that rifle in which the cases were fired does not have a particularly oversized chamber.

Some things to note about the loading data on this page;

303 British
Bullet 156 grain Lead Spire Point Gas Check, LEE C312-155-2R
Powder 23.0 grains IMR 4227
Primer CCI #34
Cartridge Case Prvi Partizan
Firearm Lee Enfield Rifle No.4 Mark 1
Barrel Length 25.2 inches
Avg Muzzle Velocity 1849 feet per second

Rear sight set to 500 yard setting to hit at 100 yards. Some vertical stringing

303 British
Bullet 152 grain Lead Spire Point plain base, LEE C312-155-2R
Powder 6.1 grains Alliant Bullseye
Primer CCI 200
Cartridge Case Remington
Firearm Lee Enfield Rifle No.4 Mark 1
Barrel Length 25.2 inches
Avg Muzzle Velocity 1079 feet per second

Some of my other cast bullet handloads for 303 British can be found on the Reduced Power Rifle loads page.

Harris, C.E. "DON'T OVERLOOK THE LEE-ENFIELD" American Rifleman July 1993 p. 46-49, 74-75
Harris, C.E. ""Handloading The .303 British" American Rifleman March 1993 p. 16, 18-20

The author of this page can be contacted at loreofguns at gmail.com