The barrel is one of the most critical components of your build. We only offer high quality barrels so you can be confident that your rifle will be off to a good start with which ever barrel you decide on.Features: 18" CHF Barrel Cold Hammer Forged DIN 21CrM0V511 Black Nitrite Inside and Out 1/7 Twist Rate 1/2 X 28 Thread Pitch for Muzzle 5.56 Nato Chamber .750 Gas Block Seat NIB M4 Feed Ramped Barrel Extension Rifle Gas