NEW Light Weight AIM AR 5.56/.223/.300 BLACKOUT complete Titanium Nitride Bolt Carrier Groups. Only 8.9 ounces! Almost 28% in weight savings over our standard Nitride BCG! Titanium Nitride is an extremely hard ceramic coating used in aerospace and military applications that improves the maintenance, cleaning, edge retention and corrosion resistance of the bcg. Features 9310 Bolt Material; 8620 carrier and gas key; Properly staked Investment cast gas key hardened to USGI specifications fastened with Hardened Grade 8 Fasteners; Shot peened MPI (Magnetic Particle Inspected) Bolt. Extractor insert installed.