2A Armament 223, Bolt Carrier Group, QPQ Nitride, Lightweight BCG, Carrier: 8620 steel, Bolt: 9310 steel, Rear body: 7075-T6 Aluminum 2A-LWBCG-S The 2A Armament Lightweight Bolt Carrier (LBC) is a lightweight carrier solution for those looking to reduce both felt recoil" and over all weight of the AR-15 pattern rifle. The LBC combines a very high quality forward body and an advanced bearing surface aluminum tail to give the shooter a reliable" lightweight" and high quality bolt carrier group. The advanced finned design of the tail section of the LBC reduces drag and wear within the receiver extension which increases reliability. The LBC is intended for rifles equipped with an adjustable gas system.