Radian Weapons Enhanced Black Nitride Bolt Carrier Group BCG AR15/M16 Nitride. These Radian Weapons Bolt Carrier Groups feature a shot peened bolt that meets and exceeds Mil-Spec standards. In addition the Radian Weapons Black Nitride Bolt Carrier Group BCG has grade 8 hardware that is the pinnacle of performance reliability and durability. The Radian Weapons Enhanced AR15/M16 Bolt Carrier Group BCG is sleek reliable and durable on and off the range. Specifications for Radian Weapons Enhanced Black Nitride Bolt Carrier Group (BCG): Manufacturer: Radian Weapons Color: Black Finish: Nitride Fabric/Material: 9310 Steel Carrier Material: 8620 Steel Bolt Material: 9310 Steel Caliber: 5.56x45mm NATO .223 Remington Gun Model: M16 AR-15 Hand: Right Weight: 11.4 oz Condition: New Country of Origin: USA Features of Radian Weapons Enhanced Black Nitride Bolt Carrier Group (BCG): Bolt: Case hardened 9310 steel shot peened w/ black nitride finish. Carrier: Billet machined case hardened 8620 steel w/ black nitride finish. Gas Key: 4130 steel attached using Grade 8 hardware and proper staking techniques. Package Contents: Radian Weapons Enhanced Black Nitride Bolt Carrier Group (BCG) What firearm models does the manufacturer say Radian Weapons Enhanced Black Nitride Bolt Carrier Group (BCG) is compatible with? The manufacturer suggests that Radian Weapons Enhanced Black Nitride Bolt Carrier Group (BCG) is compatible with AR-15 M16Radian Weapons R0081: Enhanced Black Nitride Bolt Carrier Group AR15/M16 Nitride