Ruger's AR-556 is made from 7075-T6 hard-coat anodized aluminum forgings, shot-peened and proof-tested 9310 steel bolt, and 8620 steel bolt carrier. Its barrel nut and delta ring allow easy, one-person service of the heat-resistant glass-filled nylon handguard. The design accepts most standard carbine-length handguards. Handguards are made from heat-resistant glass-filled nylon for shooting comfort and durability. The gas block is located at a carbine-length (M4) position for improved balance and handling. Serrations on the angled face of the gas block provide a low-glare surface. A single-stage trigger provides durable and reliable fire control.