With your AR15 Upper & Carrier, this 7.62 X 39mm Caliber Windham Weaponry Barrel Kit gives you the conversion parts need to build up a 7.62 x 39mm Upper Rec. Assembly. It is 16″ in length in an M4 profile, and includes the Barrel Nut, Front Handguard Cap, a Mil Std 1913 Railed Sight Base with Sling Swivel, a 7.62 x 39mm Bolt and a 7.62 x 39mm enhanced firing pin. Machined from 4150 Chrome Moly Vanadium 11595E Steel, this highly accurate barrel is Chrome Lined in both Bore and Chamber for long wear and ease of cleaning. A Black Manganese Phosphate finish offers protection against rust and corrosion. Rifling is 1 turn in 9.5 inches – right hand twist – with 4 lands & grooves for optimum accuracy with a wide range of 7.62 X 39mm ammunition. The muzzle is threaded 5/8″ x 24 T.P.I. to accept the supplied flash hider.