This Windham Weaponry Barrel is unique in that it is rifled 1×7″ Right Hand Twist instead of our more common 1 x 9″ rifling. It is turned with the M4 profile, and includes the Barrel Extension (with M4 Feed Ramps), Barrel Nut, Front Handguard Cap, A2 Standard Sight Base with Sling Swivel, Front Sight Post , Front Sight Detent, and Bayonet Lug. Machined from 4150 Chrome Moly Vanadium 11595E Steel, it is Chrome Lined in both Bore and Chamber for long wear and ease of cleaning and then Black Manganese Phosphate finished for protection against rust and corrosion. The muzzle is threaded 1/2″ x 28 T.P.I. to accept a variety of flash hiders or muzzle brakes.