This is our premium M4 Barrel in a 14.5” length with a permanently affixed A2 Extended Birdcage Flash Hider. Its 16 3/8” overall length makes it legal for use on standard semi-auto rifles. It has the M4 profile turning, and includes all parts forward of the Upper Receiver: Barrel Extension (with M4 Feed Ramps), Barrel Nut, Delta Ring, Weld Spring, Snap Ring, Gas Tube, Gas Tube Spring Pin, M4 Double Heatshield Handguards, Front Handguard Cap, A2 Standard Sight Base with Sling Swivel, Front Sight Post and Front Sight Detent. This highly accurate barrel is machined from 4150 Chrome Moly Vanadium 11595E Steel, is 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. It is button rifled 1 turn in 7 inches – right hand twist to stabilize bullets from 50 to 77 grains.