Beginning in 1901, trials were conducted at the Royal Small Arms Factory (RSAF) in Enfield on the new short rifle, resulting in the adoption in December 1902 of the Short Magazine Lee-Enfield Mk I. (marked "SHT L.E." and "I"). Production of the SMLE Mk I began in 1903 at RSAF Enfield and in 1904 at RSAF Sparkbrook, the Birmingham Small Arms Co. (BSA), and the London Small Arms Co. (LSA). Minor modifications led to the adoption of the SMLE Mk I* in 1906, with production at Enfield, Sparkbrook, BSA Co., and LSA Co.
In 1903, conversions of various "Long Lees" to SMLE configuration were approved. These converted rifles were designated SMLE Converted Mk II (marked "SHT L.E." and "ConD II" with varying numbers of stars, or asterisks). "ConD" is an abbreviation for "Converted." In 1907, additional conversions were approved, designated SMLE Converted Mk IV (marked "SHT L.E." and "ConD IV").