Up to 21% lighter than a standard Mil-Spec M16 BCG, the FailZero AR-15 .223 / 5.56 Lightweight Nickel Boron Bolt Carrier Group comes fully assembled for smooth and consistent performance you can depend on right out of the box. Featuring a skeletonized, heat-treated 8620 steel body, this BCG boasts an EXO nickel boron coating that provides enhanced friction resistance and increased wear and corrosion resistance for long-lasting service in any shooting environment. Plus, the ramped carrier design helps reduce stress on the hammer for enhanced longevity. Includes bolt and extractor, bolt carrier, extractor, cam pin, carrier key, and firing pin. Compatible with Mil-Spec AR-15 receivers. Order yours today!