This M4 profile Barrel Kit for 7.62x39mm caliber is 16” in length, 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. A Bolt specifically designed for 7.62 caliber is included – it is marked with 3 rings just behind the bolt head for safety and ease of caliber identification. This premium barrel is machined from 4150 Chrome Moly Vanadium 11595E Steel, Chrome Lined in both Bore and Chamber for long wear and ease of cleaning and Black Manganese Phosphate finished for protection against rust and corrosion. They are button rifled 1 turn in 9.5 inches – right hand twist for optimum accuracy with a wide range of 7.62x39mm ammunition. The muzzle is threaded 5/8” x 24 T.P.I. to accept a variety of flash hiders or muzzle brakes.