Watchtower Firearms Durabolt 5.56 DB-556 Bolt Carrier Group BCG are designed for AR-15 platforms. Watchtower Firearms uses high quality coatings on these Bolt Carrier Groups to resist corrosion and provide excellent durability. Every Watchtower Firearms Durabolt 5.56 AR-15 Bolt Carrier Group BCG is made with precision CNC machining and subjected to thorough testing before being sent out for sale. Customize your rifle and start shooting with more accuracy and precision with an Watchtower Firearms Durabolt 5.56 AR15 BCG. Specifications for Watchtower Firearms Durabolt 5.56 Bolt Carrier Group (BCG): Manufacturer: Watchtower Firearms Caliber: 5.56x45mm NATO Gun Model: AR-15 Features of Watchtower Firearms Durabolt AR15 Bolt Carrier Group BCG, 5.56: Compatible with any Mil-Spec components For AR-15 Direct impingement Full auto rated M16/M4 8620 high-grade steel Chrome-lined interior Carpenter 158 bolt with spring and ejector 17-4 firing pin Durabolt cam pin Package Contents: Watchtower Firearms Durabolt 5.56 Bolt Carrier Group