Sterling submachine gun
The Sterling submachine gun is a British submachine gun (SMG). It was tested with the British Army in 1944–1945 as a replacement for the Sten but it did not start to replace it until 1953. A successful and reliable design, it remained as standard issue with the British Army until 1994, when it began to be replaced by the L85A1 assault rifle. History. In 1944, the British General Staff issued a specification for a new submachine gun to replace the Sten. It stated that the new weapon should weigh no more than six pounds (2.7 kg), should  fire 9×19mm Parabellum ammunition, have a rate of fire of no more than 500 rounds per minute and be sufficiently accurate to allow five consecutive shots (fired in semi-automatic mode) to be placed inside a one-foot-square (30 cm × 30 cm) target at a distance of . To meet the new requirement, George William Patchett, the chief designer at the Sterling Armaments Company of Dagenham, submitted a sample weapon of new design in early 1944. The first Patchett prototype gun was similar to the Sten insofar as its cocking handle (and the slot it moved back and  forth in) was placed in line with the ejection port though it was redesigned soon afterwards and moved up to a slightly offset position. The army quickly recognised the Patchett's significantly increased accuracy and reliability compared to the Sten and ordered 120 examples for trials. Towards the end of the Second World War, some of these trial samples were used in combat by airborne troops during the battle of Arnhem and by special forces at other locations in Northern Europe where it was officially known as the Patchett Machine Carbine Mk 1. For example, a Patchett submachine gun (serial  numbered 078 and now held by the Imperial War Museum), was carried in action by Colonel Robert W.P. Dawson while he was Commanding Officer of No. 4 Commando, during the attack on Walcheren as part of Operation Infatuate in November 1944. Because the Patchett/Sterling can use straight Sten magazines as well as the curved Sterling design, there were no interoperability problems. After the war, with large numbers of Sten guns in the inventory, there was little interest in replacing them with a superior design. However, in 1947, a competitive trial between the Patchett, an Enfield design, a new BSA  design and an experimental Australian design was held, with the Sten for comparison. The trial was inconclusive but was followed by further development and more trials. Eventually, the Patchett design won and the decision was made in 1951 for the British Army to adopt it. It started to replace the Sten in 1953 as the "Sub-Machine Gun L2A1". Its last non-suppressed variation was the L2A3 but the model changes were minimal throughout its development life. Sterling submachine guns with minor cosmetic alterations were used in the production of the "Star Wars" films as Stormtrooper blaster rifle props. Design  details. The Sterling submachine gun is constructed entirely of steel and plastic and has a shoulder stock, which folds underneath the weapon. There is an adjustable rear sight, which can be flipped between 100 and 200 yard settings. Although of conventional blowback design firing from an open bolt, there are some unusual features: for example, the bolt has helical grooves cut into the surface to remove dirt and fouling from the inside of the receiver to increase reliability. There are two concentric recoil springs which cycle the bolt, as opposed to the single spring arrangement used by many other SMG  designs. This double-spring arrangement significantly reduces "bolt-bounce" when cartridges are chambered, resulting in better obturation, smoother recoil and increased accuracy. The Sterling's 34-round curved double-column feed boxmagazine was designed in 1946 by George Patchett. While the Sterling was originally intended to take Sten magazines, due to a lack of reliability, a new magazine was constructed, with many changes, including the implementation of rollers to reduce friction, a stamped metal construction, and the magazine was curved, which allowed the 9×19mm round to feed more reliably. The bolt feeds ammunition alternately from the top and bottom  of the magazine lips, and its fixed firing pin is designed so that it does not line up with the primer in the cartridge until the cartridge has entered the chamber. The Sterling magazine is said to be one of the best ever designed. The Sterling employs a degree of what is known as Advanced Primer Ignition, in that the cartridge is fired while the bolt is still moving forward, a fraction of a second before the round is fully chambered. The firing of the round thus not only sends the bullet flying down the barrel but simultaneously resists the  forwards movement of the bolt. By this means it is possible to employ a lighter bolt than if the cartridge was fired after the bolt had already stopped, as in simple blowback, since the energy of the expanding gases would then only have to overcome the bolt's static inertia (plus spring resistance) to push it backwards again and cycle the weapon; whereas in this arrangement some of this energy is used up in counteracting the bolt's forwards momentum as well; and thus the bolt does not have to be so massive. The lighter bolt makes not only for  a lighter gun, but a more controllable one since there is less mass moving to and fro within it as it fires. The suppressed version of the Sterling (L34A1/Mk.5) was developed for covert operations. This version uses a ported barrel surrounded by a cylinder with expansion chambers. The Australian and New Zealand SAS regiments used the suppressed version of the Sterling during the Vietnam War. It is notable for having been used by both Argentinian and British Special Forces during the Falklands War. A Sterling was used by Libyan agents to kill WPC Yvonne Fletcher outside the Libyan Embassy  in London, which sparked the 1984 siege of the building. The Sterling has a reputation for excellent reliability under adverse conditions and, even though it fires from an open bolt, good accuracy. With some practice, it is very accurate when fired in short bursts. While it has been reported that the weapon poses no problems for left-handed users to operate, it is not recommended without the wearing of ballistic eye protection. The path of the ejected cartridge cases is slightly down and backward, so mild burns can occasionally be incurred by left-handed shooters. A bayonet of a similar  design as that for the L1A1 Self-Loading Rifle was produced and issued in British Army service, but was rarely employed except for ceremonial duties. Both bayonets were derived from the version issued with the Rifle No. 5 Mk I "Jungle Carbine", the main difference being a smaller ring on the SLR bayonet to fit the rifle's muzzle. When mounted, the Sterling bayonet was offset to the left of the weapon's vertical line, which gave a more natural balance when used for bayonet-fighting. For a right-handed shooter, the correct position for the left hand while firing  is on the ventilated barrel-casing, but not on the magazine, as the pressure from holding the magazine can increase the risk of stoppages, and a loose magazine can lead to dropping the weapon. The barrel-casing hold provides greater control of the weapon, so the right hand can intermittently be used for other tasks. A semi-circular protrusion on the right-hand side of the weapon, approximately two inches from the muzzle, serves to prevent the supporting hand from moving too far forward and over the muzzle. Manufacture. A total of over 400,000 were manufactured between 1953 and 1988 . Sterling built them at their factory in Dagenham for the British armed forces and for overseas sales, whilst the Royal Ordnance Factories at Fazakerley near Liverpool constructed them exclusively for the British military. Production ceased in 1988 with the closing of Sterling Armaments by British Aerospace/Royal Ordnance. ROF no longer makes full weapons, but still manufactures spare parts for certified end users. A Chilean variant was made by FAMAE as the PAF submachine gun but was different externally as it had a shorter receiver lacking the barrel shroud. Canada also manufactured a variant under licence, called the Submachine Gun  9 mm C1 made by Canadian Arsenals Limited. It is made from stamped metal instead of cast metal and is capable of handling a C1 bayonet, which is only used during public exhibition events and not for combat operations. A similar weapon, the Sub-Machine Gun Carbine 9 mm 1A1, was manufactured under licence by the Indian Ordnance Factory at Kanpur beginning in 1963, along with a Sub-Machine Gun Carbine 9 mm 2A1, manufactured beginning in 1977. As of 2012, it has been reported that at least 5,000 of these SMGs were made in India. Variants. 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.