American Built Arms Company Bolt Carrier Group 5.56mm AR-15 Nickel Boron - ABA556B

This is a complete bolt carrier group (BCG) designed for 5.56mm AR-15 platforms, featuring a nickel boron finish for enhanced durability and reduced friction. The nickel boron coating provides superior corrosion resistance and easier cleaning compared to standard phosphate finishes. Direct drop-in compatible with mil-spec AR-15 receivers.