Luth-AR Complete Upper Receiver Assembly .223 31in 24in Bull Rifle 1x9 1/2x28 Picatinny Key MOD A2 Flash Hider Anodized Manganese Phosphate Silver/. 223 Caliber fluted bull barrel made from 416 SST with a 1-9 twist mated to Luth-AR A3 Flattop receiver...