This Kit for 7.62x39mm caliber includes all parts forward of the Upper Receiver as well as a 7.62 specific Bolt and Firing Pin. The M4 profile Barrel 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. Other included parts are a set of Double Heatshield Handguards, Delta Ring components (Delta Ring; Weld Spring And Snap Ring), Gas Tube and Spring Pin, and A2 Flash Hider with Crush Washer. The Bolt – specifically designed for 7.62 caliber – is marked with 3 rings just behind the bolt head for safety and ease of caliber identification and a 7.62 specific firing pin is also included – marked with one machined ring around the head of the pin. 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.