Black River Tactical M4A1 BCG is a Full Auto Bolt Carrier Group made to current USGI M4A1 specifications.
- Full Auto Bolt Carrier Group BCG for the AR Family of Weapons (AR-15, M16, M4)
- Carpenter 158 bolt is Shot Peened, HP tested and MP inspected.
- The USGI full auto bolt carrier is Hard Chrome lined inside and Manganese Phosphate coated outside.
- The Mil-Spec gas key is chrome lined, secured with mil drawing heavy splined fasteners and properly staked to ensure reliable gas system performance.
- Bolt is marked “MP”. Carrier is marked “BRT” with Logo on the ejection port side.
- 100% made in USA to current USGI M4A1 specifications.