Russell Turner was a Pennsylvania gunsmith and inventor who developed this semiautomatic conversion of an SMLE bolt action rifle circa 1940. It was intended for trial and potential sale to the Canadian military, as it would allow them to retrofit existing rifles into semiautomatic configuration and still use existing supplies of .303 British ammunition. Rather than try to devise a reliable system to rotate the original Enfield bolt, Turner replaced the bolt entirely, using instead a side-tilting design much like what he used in his M1 Carbine trials rifle for the US military.
