The SIG SG 550 is the standard service rifle of the Swiss Army, adopted in 1990 as the Sturmgewehr 90 (Stgw 90). Chambered in 5.56x45mm NATO, it is widely regarded as one of the finest service rifles ever produced, noted for exceptional accuracy, reliability in extreme cold, and superb build quality. The SG 550 features a distinctive thumbhole polymer stock with transparent magazines that can be coupled together. Type: Rifle Action: Semi/Full-Auto Caliber: 5.56x45mm Capacity: 20 Year introduced: 1986, Switzerland Weight: 144 oz Overall length: 39.4" Status: Active Military use: Yes Intended use: military