Sons of Liberty Gun Works AR-15 5.56x45mm NATO/.223 Remington OCKS Bolt Carrier Group Nickel Teflon Finish Nickel. If the gas port is the lungs then the bolt carrier group is the heart. It's what drives the entire gun. If you look at the AR platform's cycle of operations everything happens around the bolt carrier group. Locking unlocking extracting ejectingall of it begins with the bolt carrier group. Specifications for Sons of Liberty Gun Works AR-15 5.56x45mm NATO/.223 Remington OCKS Bolt Carrier Group: Manufacturer: Sons of Liberty Gun Works Caliber: .223 Remington 5.56x45mm NATO Gun Make: AR Platform Gun Model: AR-15 Package Contents: Sons of Liberty Gun Works AR-15 5.56x45mm NATO/.223 Remington OCKS Bolt Carrier Group What firearm models does the manufacturer say Sons of Liberty Gun Works AR-15 5.56x45mm NATO/.223 Remington OCKS Bolt Carrier Group is compatible with? The manufacturer suggests that Sons of Liberty Gun Works AR-15 5.56x45mm NATO/.223 Remington OCKS Bolt Carrier Group is compatible with AR-15Sons of Liberty Gun Works SOLGW-BCG556-NTC: AR-15 5.56x45mm NATO/.223 Remington OCKS Bolt Carrier Group Nickel Teflon Finish Nickel