AR-15 5.56/.223 18" classic upper assembly (also available in 18" stainless steel barrel) features:
Barrel - 18" 416 stainless steel gov. contour barrel. Hardened to 26-32 rc and stress releived. Chambered in 5.56 nato (also accepts .223 rounds). 1-8 rh twist. Button rifled. .750 under gas block. Barrel is finished off with a black muzzle brake and crush washer. M4 feedramps.
A3 flat top upper reciever - made from certified 7075-t6 aluminum forgings. Black hardcoat anodized coated to gov. specs. Forward assist and dust cover installed. M4 feedramps.
Gas system - .750 low profile aluminum gas block, hardcoat anodized. Mid length gas tube.
Handguards - Free float mid-length quadrail handguard, anodized black.