RIMLESS .303?
(from AR, Q&A, Dec93, p51)
Q: I have a rimless cartridge in my collection with a British military headstamp, "R^L 18". The case body is wider and the neck longer than the rimmed .303 British, but overall length and rim diameter are the same. Did the British make a rimless .303?
A: The cartridge you describe is known as a .303 Lewis or .303 Lewis Rimless. According to Fred A. Datig's CARTRIDGES FOR COLLECTORS, VOLUME I, it was developed experimentally by the British around the end of World War I to help improve the performance of the American-designed Lewis machine gun.
The Berdan-primed case body was enlarged to .503" and the neck lengthened. To make chamber conversions easier, the rim diameter and overall length were kept the same, but varied considerably in the other dimensions (see accompanying table). The propellant was Cordite and the bullet cupro-nickel covered. The Royal Laboratory, Woolwich, indicated by the "R^L", was the center of British cartridge development during this period. -- M.A.K.
NOMINAL CARTRIDGE .303 Lewis .303 Mark
DIMENSIONS Rimless VII Ball
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Overall Length 3.04" 3.04"
Case Length 2.42" 2.21"
Neck Diameter .343" .333"
Head Diameter .503" .458"
Rim Diameter .530" .530"
Bullet Diameter .300" .311"
Bullet Weight 173grs 174grs
