A semi-automatic, M4-Style, direct impingement Modern Sporting Rifle, the AR-556® offers consumers an affordable, American-made rifle with the rugged reliability they have come to expect from Ruger. Extensively tested during its development, the AR-556® is constructed from top-quality components, including forged 7075-T6 aluminum upper and lower receivers and a cold hammer-forged, chrome-moly steel barrel with M4 feed ramp cuts. Chambered in 5.56 NATO with standardized M4/AR components utilized throughout, the AR-556® is easily customizable.