The AR-15 Nickel Boron Bolt Carrier Group is a high-performance, MIL-SPEC BCG with a durable nickel boron coating for superior corrosion resistance, reduced friction, and easy cleaning. It undergoes rigorous HPT and MPI testing to ensure reliable performance under stress. Designed for 5.56/.223 and 300 Blackout calibers, this BCG offers exceptional reliability and durability, making it ideal for both replacements and new builds.