The SIG SG 510 or also Sturmgewehr 57 is originally an automatic army rifle designed (1950) by the Schweizerische Industrie Gesellschaft (SIG) in Neuhasen and put into active service with the Swiss Army in 1957. The SG 510 replaced the K31 repeating rifle in the arsenal from which it took the popular bolt pull lever. The rifle also adopted the standard service calibre of 7.5 x 55 Swiss.
Technical highlights include the folding "winter" trigger. This allows the shooter to shoot while wearing gloves, which would be minimally difficult with a conventional bow trigger. The relatively massive 24" (609 mm) barrel is topped by a 26 mm (24 in) muzzle brake, which, in combination with the chambering system with cartridge lock and recoil spring, reduces the recoil of the gun by up to 25%. The barrel is concealed beneath a perforated aluminum receiver with spring loaded bipod slide stops.
Despite the original military nature of the rifle, the Stgw 57 is extremely accurate at longer ranges, which is why it is often seen at shooting competitions these days. The sights on the gun are folding and the scope is adjustable. Due to the design and balance of the gun to the barrel, it is more difficult to shoot standing up. In total, more than 700,000 units were produced. The Stgw 57 rifle was replaced by the SIG SG 550 / Stgw 90 rifle in 1990.