American Built Arms Company Pro 5.56mm Bolt Assembly Silver/Black Small

American Built Arms Company Pro 5.56mm Bolt Assembly Silver/Black Small. For superior reliability these Bolt Carrier Groups feature a nickel boron coated bolt and extractor each crafted from heat-treated steel. A nickel boron coated bolt assembly has reduced friction and requires less maintenance than standard assemblies. Drop this AB Arms 5.56 bolt assembly into your AR-15 to guarantee your rifle will perform when it matters most. Specifications for American Built Arms Company Pro 5.56mm Bolt A