This AR15 Complete Upper Receiver Assembly in 7.62 X 39mm Caliber features an A2 Front Sight with Sling Swivel and Bayonet Lug. The complete assembly includes a 16″ M4 profile Barrel in 7.62 X 39mm with Handguards, a 7.62 x 39mm Bolt & Bolt Carrier, and a quality 30 Round 7.62 Magazine. 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. The Barrel is 4150 Chrome Moly Vanadium 11595E Steel, Chrome Lined in Bore and Chamber, rifled 1 turn in 9.5 inches – right hand twist – with 4 lands & grooves. The muzzle is fitted with an A2 Birdcage Type Flash Hider (threaded 5/8 x 24). Laser engraved receiver markings identify it as 7.62×39 caliber for your safety.