AR-15 Bolt Carrier Group (BCG) Buyers Guide: Treatments, Materials, & Specs
This guide, drawing from Mrgunsngear's expertise, details the critical components and specifications of an AR-15 Bolt Carrier Group (BCG). It covers essential materials like 158 Carpenter Steel and 9310 Steel for bolts, and 8620 Steel for carriers, alongside vital testing standards (HP and MP) and durability treatments like shot peening and chrome lining. The guide also differentiates between full-auto and semi-auto carriers and stresses the importance of proper gas key staking for reliability.












