This Windham Weaponry “MPC” type M4 Barrel – 16” in length – has the M4 profile turning, and a permanently affixed A2 birdcage style compensator to comply with MA and NJ specifications. The barrel extension has the M4 style feed ramps — also included are the Barrel Nut, Front Handguard Cap, A2 Standard Sight Base with Sling Swivel, Front Sight Post and Front Sight Detent. 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. Button rifling is 1 turn in 9 inches – right hand twist to stabilize most .223 Rem. / 5.56 mm NATO bullets.