16&rdquo; Stainless Steel 416R Contour Barrel Carbine Gas w/1:8 Twist .223 5.56 NATO Caliber Wylde Chambered 16 inch length Barrel .223 and 5.56 MSTO Wylde Chambered 1 in 8 Twist Rate Stainless Steel 416R Carbine-Length Gas System