Noveske Bolt Carrier Group for 5.56 NATO/300 Blackout DLC Finish Black. Machined to USGI specifications and made out of Aircraft grade 8620 Steel. This M16/M4 carrier includes mil-spec gas key which is chrome lined and heat treated. Specifications for Noveske Bolt Carrier Group for 5.56 NATO/300 Blackout DLC Finish Black: Manufacturer: Noveske Color: Black Finish: DLC Black Additional Features: Bolt Carrier Group Case Finish: DLC Handle Color: Black Blade Finish: DLC Features of Noveske Bolt Carrier Group for 5.56 NATO/300 Blackout DLC Finish Black: DLC Exterior Coat for Wear Resistance Package Contents: Noveske Bolt Carrier Group for 5.56 NATO/300 Blackout DLC Finish Black