Cryptic Bolt Carrier Group BCG - Complete .308 WIN/7.62x51mm/6.5 Creedmoor Mystic Black. 308 WIN / 7.62x51mm / 6.5 Creedmoor) machined from Mil-Spec 8620 aircraft quality steel with shrouded firing pin and Mil-Spec chrome lined interior. BCG includes the proper chrome lined and heat treated gas key. Gas key is secured to carrier with Grade 8 fasteners and properly staked per Mil-Specs. This ensures a strong staking and proper gas system functioning. The bolt assembly is CNC machined from Mil-Spec Carpenter No. 158 steel and shot peened for increased strength per Mil-Spec. HPT (High Pressure Batch Tested) and MPI (Magnetic Particle Inspected). Specifications for Cryptic .308 WIN/7.62x51mm/6.5 Creedmoor Bolt Carrier Group (BCG) - Complete: Manufacturer: Cryptic Finish: Chrome Plated Fabric/Material: 8620 Aircraft Quality Steel Carpenter 158 Steel Carrier Material: 8620 Steel Bolt Material: Steel Caliber: 7.62x51mm NATO 6.5mm Creedmoor .308 Winchester Gun Make: AR Platform Gun Model: DPMS LR-308 AR-10 Hand: Ambidextrous Weight: 17.8 oz Condition: New Included Accessories: Standard Features of Cryptic .308 WIN/7.62x51mm/6.5 Creedmoor Bolt Carrier Group BCG - Complete Reduced Carbon Fouling; Easier Cleaning; Full Auto Carrier (Backward compatible with all semi-auto rifles) Package Contents: Cryptic .308 WIN/7.62x51mm/6.5 Creedmoor Bolt Carrier Group - Complete Gas Key Key Staked with Grade 8 Screws Bolt w/ Spring and Ejector Extractor w/ Spring Firing Pin Cam Pin What firearm models does the manufacturer say Cryptic .308 WIN/7.62x51mm/6.5 Creedmoor Bolt Carrier Group (BCG) - Complete is compatible with? The manufacturer suggests that Cryptic .308 WIN/7.62x51mm/6.5 Creedmoor Bolt Carrier Group (BCG) - Complete is compatible with AR-10 DPMS LR-308Cryptic CC-0200: Bolt Carrier Group - Complete .308 WIN/7.62x51mm/6.5 Creedmoor Mystic Black