This AR-STONER AR-15 Barrel is perfect for use in competition where both accuracy and reliable functioning are very important factors to a successful match. The barrel uses the popular and versatile 223 Wylde chamber, which has a longer throat than the SAAMI spec for 223 Remington to allow for the safe usage of 5.56x45mm NATO ammunition and enhanced reliability. However, accuracy potential is also greater than a 5.56 NATO chamber due to slightly tighter tolerances, making the 223 Wylde an ideal compromise that retains the benefits of both of the other two chamber options. This Medium Contour Barrel is manufactured from 416R Stainless Steel and uses 5R Rifling with a 1 in 8" Twist. Additional features include a Mid Length Gas Port, M4 Feed Ramps and 1/2"-28 threaded muzzle. Barrel extension and locator pin are both included and installed at the factory. Features:Chambered in 223 Remington Wylde1:8 TwistStainless Steel