This kit offers the unique Windham Weaponry .223/5.56 Cal. pencil barrel and all parts forward of the upper receiver for assembly by the home gunsmith. 16″ in length, the barrel is turned in a narrow pencil profile, with a .625” diameter at the gas block location, and includes the barrel extension, standard barrel nut, round front handguard cap, and an A2 fixed front sight base (installed with front sight post, detent, detent spring, sling swivel, and rivet). A set of carbine length handguards, gas tube, gas tube pin, delta ring kit, A2 flash suppressor and crush washer are also included. Machined from 4150 chrome moly Vanadium 11595E steel, this highly accurate barrel has a Melonite QPQ finish inside and out for long wear and ease of cleaning. As well as offering protection against rust and corrosion. Rifling is 1 turn in 9” with a right hand twist and the muzzle is threaded 1/2″ x 28 T.P.I.