Guntec USA Ar-15 Nitride Skeletonized Bolt Carrier Group BCG Black Nitride. Crafted to perfection with ultra precise CNC machines each bolt carrier group is machined with the same care and concern that is put into every part we sell. This complete low drag Bolt Carrier Group is ready to ship and is optimized to produce less internal wear leading to increased reliability and durability. This is a dependable solution for shooters that need reliability and performance from their bolt carrier group but demand the best in quality and function. Each group is Nitrided and QPQ treated to resist corrosive elements and abrasion. Your group will be shooting on target with improved accuracy and improved reliability as a result. Specifications for Guntec USA Ar-15 Nitride Skeletonized Bolt Carrier Group (BCG): Manufacturer: Guntec USA Fabric/Material: 9310 Steel Bolt Carrier Material: 8620 Steel Bolt Material: 9310 Steel Caliber: .223 Remington Gun Make: AR Platform Gun Model: AR-15 Hand: Right Weight: 10.4 oz Included Accessories: None Package Contents: Guntec USA Ar-15 Nitride Skeletonized Bolt Carrier Group What firearm models does the manufacturer say Guntec USA Ar-15 Nitride Skeletonized Bolt Carrier Group (BCG) is compatible with? The manufacturer suggests that Guntec USA Ar-15 Nitride Skeletonized Bolt Carrier Group (BCG) is compatible with AR-15Guntec USA GT-BCG-LM: Ar-15 Nitride Skeletonized Bolt Carrier Group Black Nitride