Stern Defense Nickel Boron 9mm Complete Bolt Carrier Group - SD BU9 NiB ECHO

- Nickel Boron 9mm Complete Bolt Carrier Group by Stern Defense - Material: 8620 AISI steel - Finish: NiB (Nickel Boron) - Fits Mil-Spec and Glock-pattern upper receivers - Compatible with Colt SMG and Glock magazines - Compatible with standard AR-15 / M16 charging handles - Comes fully assembled with all sub-components installed, including firing pin, firing pin spring, retaining pin, extractor, and extractor spring - Also included in bolt assembly is a propriety center and roll pins - 9mm bolts incorporate a new bolt design