American Built Arms 5.56 Bolt Carrier Group is built to Mil-Spec dimensions. The Nickel Boron coated Bolt and Cam Pin needs virtually no lube during use. The Nickel Boron coated Carrier is coated for extra lubricity and the phosphate coated extractor has a surface finish that provides superior extraction during firing.
These Bolt Carrier Groups are ready to drop into your rifle. Our Bolt Carrier Groups are specially made on high end Swiss machinery to have exacting tolerances and surface finish. A*B Arms is known by rifle manufacturers for manufacturing one of the finest quality bolts and extractors available. This has won us contracts with some of the highest quality AR manufacturers in the business. If you want to buy super high quality parts offered by the company that actually manufactures them, then you've come to the right place.
- Carpenter 158 Steel - Heat treated per Mil-Spec Requirements - Shot Peened per Mil-Spec Requirements - MPI Tested Material - Nickel Boron Coated
- 8620 Steel - Nickel Boron Coated - Nickel Boron Coated Bore - M-16 Style with more mass for better functioning in semi or full auto rifles
- 4130 Steel - Nickel Boron Coated - Gas Key Screws - 4140 Steel properly staked per Mil-Spec requirements