DealSt Croix Tactical Nitride Bolt Carrier Group - AR15/M16 5.56/.223, 9310 Steel Bolt Nitride, MPI Bolt (Magnetic Particle Inspected), Shot Peened Bolt, Nitride Carrier (Auto), Nitride Gas Key, Grade 8 Hardened Fasteners, Key Staked per Mil-Spec, Black Extractor Insert with Crane O-Ring. from Ground Zero Precision (Product SCT-556-QPQ-BCG) |