Introducing the Brownell’s Retro A1 rifle length barrel assembly. Chambered in 5.56x45, the chrome lined barrel has a 1-7 twist and finished in black phosphate with an overall length of 20”. Muzzle threads are ½-28 and features a standard rifle barrel extension. The assembly includes a front sight base, .625 No F Marks, sight post, detent, spring, sling swivel, rivet, flat delta ring, barrel nut, weld spring, snap ring, and triangular handguard cap. Everything you need for your Retro barrels!