Guntec USA AR .308 Nitride Skeletonized Low Mass Bolt Carrier Group BCG Black. The goal is to distribute excellent quality at an economical value. Specifications for Guntec USA AR .308 Nitride Skeletonized Low Mass Bolt Carrier Group (BCG): Manufacturer: Guntec USA Finish: Nitride Fabric/Material: Stainless Steel Bolt Material: 9310 Steel Caliber: .308 Winchester Hand: Right Length: 11 in Weight: 16 oz Features of Guntec USA AR .308 Nitride Skeletonized Low Mass Bolt Carrier Group BCG Made for 7.62X51/308 cal. The group comes fully assembled with properly torqued and staked gas key. 8620 carrier and gas key. HPT/MPI tested and marked. Hardened extractor S7 tool steel. Skeletonized low mass design. Package Contents: Guntec USA AR .308 Nitride Skeletonized Low Mass Bolt Carrier Group Guntec USA GT-BCG-308-LM: AR .308 Nitride Skeletonized Low Mass Bolt Carrier Group Black