The F-1 Firearms DuraBolt  direct impingement full auto rated M16/M4 bolt carrier group, for use in AR15 platforms, is compatible with MIL-SPEC receivers and associated components. The DuraBolt  is enhanced with a Physical Vapor Deposition (PVD) coating, which gives it an extremely durable and corrosion resistant silver mirror finish. The DuraBolt  coating also offers excellent lubricity with a low coefficient of friction.

Carpenter 158 bolt, ground after heat treat, MPI and HPT
9310 steel carrier, ground after heat treat
Due to current demand, please allow up to 30 days for shipment