For states with regulations against bayonet lugs, flash hiders and high capacity magazines, this complete Upper Receiver Assembly in 7.62 X 39mm Caliber features a Carlson Compensator that has been pinned and welded to the barrel and a quality 10 Round Magazine. The assembly includes a 16″ M4 profile Barrel in 7.62 X 39mm with Handguards, Picatinny Railed Gas Block and laser engraved flat-top Upper Receiver. Also included is a 7.62 specific Bolt (marked with 3 rings just behind the bolt head for your safety), a 7.62 specific Firing Pin (marked with a machined groove around the pin head), Bolt Carrier, and Charging Handle. 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. Laser engraved receiver markings identify it as 7.62×39 caliber for your safety.