This M4 Barreled Upper Receiver Assembly is compliant with regulations for the States of MA and NJ. It is complete and ready to snap onto your Lower. The highly accurate 16” M4 profile barrel is chrome lined and machined from 4150 Chrome Moly Vanadium 11595E Steel with M4 feed ramps. Rifled 1 x 9” right hand twist for optimum accuracy with a wide range of .223 Rem. / 5.56mm NATO ammunition, the barrel includes a permanently affixed A2 birdcage style compensator. Standard A2 Front Sights are fitted. The machined aluminum flat top Upper Receiver is complete with Bolt Carrier Assembly, Charging Handle, Forward Assist, Ejection Port Cover, and Removable A4 Carry Handle with 300 – 600 meter Dual Aperture Rear Sight.