The Ruger SR556 is a usa-made semi-automatic rifle chambered in 5.56x45mm NATO, introduced in 2009. Primary use: sport, military, hunting. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2009, USA Weight: 112 oz Overall length: 43" Status: Discontinued Intended use: sport, military, hunting