The ALG Phosphate Mil-Spec Bolt Carrier Group (BCG) is a great replacement or backup for your current AR, or a perfect starting point for your next build. The Bolt is CNC ground after heat treat for true Mil Spec dimension’s and fit. Made of case hardened 9310 steel, shot peened, and ships with the Crane O ring installed. Our bolts are High Pressure Tested (HPT) and Magnetic Particle Inspected (MPI).
The Carrier is made of 8620 steel, the gas key is 4130 steel and is attached with Grade 8 hardware and properly staked. It has a chrome lined firing pin and chrome lined carrier as per mil-spec.
The ALG Phosphate BCG is compatible with AR15 rifles chambered in .223/5.56, and .300 Blackout