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 Imperial-issue E-11 blaster rifle props; more drastically altered Sterlings were used as Rebel Alliance-issue DH-17 blasters, though this weapon was mostly depicted via resin casts and only a few live-firing weapons were modified compared to "E-11" Sterlings. 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 double-column feed box magazine was designed in 1946 by George Patchett. While the original Patchett gun was intended to take Sten or Lanchester magazines, these magazines' lack of reliability led Patchett to initially redesign the Sten magazine with a roller platform to reduce friction, and then to construct a new double-feed magazine that implemented the earlier roller platform, a stamped metal construction, and a curved magazine body, allowing 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. In its final iteration, the magazine uses a four-piece construction with scalloped, spot-welded edges and positioning notches. While originally intended to hold forty rounds, concerns over the magazine's ability to fit into the ammunition pouch of the then-new 1944