The Phase 5 Black Phosphate Bolt Carrier Group by Phase 5 Weapon Systems is a premium choice for firearm enthusiasts seeking reliability and durability. This mil-spec M-16/M-4 bolt carrier is expertly crafted with a heat-treated and chrome-lined interior ensuring smooth functionality and long-lasting performance. The black phosphate coating adds a sleek corrosion-resistant finish making it both practical and visually appealing. This complete bolt carrier group comes ready to use and includes a cam pin firing pin gas key and bolt. Measuring 7.5 inches in length and constructed from high-quality stainless steel it is a dependable upgrade for your firearm.