SIG SG 510 (Sturmgewehr 57) — Swiss service rifle with a delayed roller-blowback action. Exceptionally accurate and well-made; the heaviest service rifle of its era at 5.7 kg empty. Chambered in the unique 7.5x55 Swiss cartridge; exported in 7.62 NATO as the AM-55. Type: Rifle Action: Gas-Operated Caliber: 7.5x55mm Swiss Capacity: 10 Year introduced: 1957, Switzerland Weight: 112 oz Overall length: 39.5" Status: Discontinued Military use: Yes Intended use: military