SIG 510 (Stgw 57)

The SIG 510, adopted by the Swiss Army as the Sturmgewehr 57 (Stgw 57), is a Cold War-era select-fire battle rifle developed by Schweizerische Industrie Gesellschaft at Neuhausen am Rheinfall. Introduced in 1957 to replace the aging Karabiner 31 straight-pull bolt-action rifle, the Stgw 57 served as the primary service rifle of the Swiss Armed Forces for over three decades until its gradual replacement by the 5.56mm SIG SG 550 beginning in 1990. The rifle operates on a roller-delayed blowback mechanism derived from the wartime German StG 45(M), placing it in the same mechanical family as the Spanish CETME and German Heckler & Koch G3. Unlike the G3 and CETME, however, the Stgw 57 was engineered to extremely tight Swiss tolerances, with a heavy milled-steel receiver, a straight-line stock layout to tame recoil, an integral folding bipod, a rubber recoil pad, a winter trigger for gloved operation, and a flip-up carrying handle. The standard Swiss variant is chambered in the domestic 7.5x55mm GP11 cartridge and fed from a 24-round detachable box magazine; export variants (SIG 510-4) were rechambered in 7.62x51mm NATO and supplied to Chile and Bolivia. Fired from the shoulder, the Stgw 57 is noted for exceptional accuracy well beyond typical battle-rifle standards, benefiting from its long 583 mm barrel, 600 mm sight radius, and adjustable diopter sights graduated to 650 meters. Its principal drawback is weight: at roughly 5.7 kg empty, it is among the heaviest battle rifles ever issued as standard infantry equipment, a consequence of the decision to build it almost entirely from machined steel rather than stampings.