This AR-STONER AR-15 223 Remington (Wylde) Barrel is perfect for competition or plinking where reliability is imperative to a successful day. This M4 contour barrel is made from 4150 Chrome Moly Vanadium Steel. Barrel extension and locator pin are both included and factory installed.Chambered in the popular 223 Wylde Chamber, this barrel has a longer throat than the SAMMI spec for 223 Remington. Allowing for safe usage of 5.56x45mm NATO ammo with enhanced reliability. Tighter tolerances also increase the accuracy potential for this barrel. These benefits make the 223 Wylde an ideal compromise between the two chamber options.