weapons that were unofficially converted into drill purpose variants prior to the 1973 standardisation of the L49A1. Sterling Mark 6 "Police": a semi-automatic-only closed-bolt version for police forces and private sales. A US export version had a longer barrel () to comply with Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) regulations. Beginning in 2009, Century Arms began marketing a similar semi-auto only carbine manufactured by Wiselite Arms. These too have a 16-inch barrel. They are assembled using a mix of newly made US parts, and parts from demilitarized Sterling Mark 4 parts kits. This is often marketed as the Sterling Sporter. Sterling Mark 7 "Para-pistol": Special machine pistol variant issued to commando and plainclothes intelligence units. It had a barrel shortened to , fixed vertical foregrip, and weighed . If used with a short 10- or 15-round magazine, it could be stowed in a special holster. It also could be used as a Close Quarters Battle weapon with the addition of an optional solid stock. Canadian Army C1 Submachine Gun: Adopted in 1958, replacing the STEN gun in general service. It was different from the British L2 in that it made extensive use of stamped metal parts rather the more expensive castings used by British production SMGs. It also had a removable trigger guard for use with gloves in arctic operations as a standard option, and used a different 30-round magazine with a stamped metal follower. A 10-round magazine was also available for crews of armoured vehicles. Indian Army SAF Carbine 1A: Indian made Sterling L2A1. SAF Carbine 2A1: Sterling Mark V silenced carbine. 7.62 NATO variant A prototype rifle in the 7.62×51mm NATO calibre was manufactured, using some components from the SMG. The rifle used lever-delayed blowback to handle the more powerful rounds and was fed from 30-round Bren magazines. To prevent ammunition cookoff, the weapon fired from an open bolt. Only one model of the rifle was produced, possibly to test the concepts of a proposed new product. It was not put into production. Users : Mk 4 variant and L34A1 suppressed variant. Frente Nacional de Libertação de Angola : Mk 4 (trials) and L34A1 suppressed variant. : L34A1 suppressed variant, used by Jagdkommando special forces only. : Mk 3 (trials) and Mk 4 variants. : Mk 4 variant. : Mk 4 variant. : Mk 3 variant, trials only : Mk 4 variant. : Produced as the