British use of 7,92x57


Quite a variety of ammunition as used in extraction tests with the British SLEM self-loading rifles, unfortunately I couldn’t find the paper listing the results.

Happy collecting, Peter


The reason for testing the SLEM1 with so many different types of 7.92mm was because of sensibility to case hardness.

The causes go back to 1937 when the Czech Zb53 was introduced to British service as the Besa Mark I. All the testing had been done with Czech ammunition and it was found that when home produced ammo by Kynoch was tested the cases were too hard and separated cases resulted. Consequently British 7.92mm ammo for the Besa was made with soft cases.

When the SLEM1 was being developed in 1944/5 it was found that the opposite was true and that the SLEM1 action needed cases of normal hardness. Woolwich produced some special hardened cases in 1946 (R^L 46 2Z) and specially selected batches of British ammunition that were at the upper end of the hardness gradient were also issued, but the best ammunition was found to be wartime German. Consequently 54,000 rounds of captured German ammunition was issued for the SLEM1 trials. It seems the memo you showed was part of this process.

ROF Radway Green made special batches of 7.92mm for the SLEM1 trials, headstamped with ground down .303 Mark VII bunters so that they read “RG I” and "RG V ". Although 100,000 rounds of the “RG V” ammunition were ordered in 1946, all work on the SLEM1 stopped in 1947.