The NBS Lightweight 5.56/.223 Nitride Bolt Carrier Group for the AR-15 platform is precision made to MIL-SPEC standards using the highest quality materials and machining available. By reducing the mass of the BCG, felt recoil is diminished, allowing you to stay on target for more accurate shooting. The NBS Lightweight BCG is perfect for competition/3-gun applications when paired with an adjustable gas block and a lighter buffer!The carrier is made from 8620 tool steel and is paired with a 9310 steel bolt. The carrier and bolt are then treated with a nitride finish to ensure longevity.Features: AR-15/M4 BCG .223/5.56 NATO Black nitride finish Magnetic particle inspected 9310 steel bolt Case hardened 8620 tool steel heat treated carrier Properly staked gas key Grade 8 fasteners 4140 steel cam pin Shot peened tool steel extractorMADE IN THE USA