The 20" 5.56 NATO barrel has a military A2 HBAR profile and is the same barrel used on our Model 4 rifle. The barrel has a 1/9 twist. The barrel extension is pre-installed and headspaced.
Chamber: 5.56 NATO (The barrel assembly will also shoot .223 ammunition)
Diameter at the gas port: .750"
Barrel Threading: 1/2x28
Barrel Profile: A2 heavy barrel (HBAR)
Barrel Material: 4140 Steel
Twist Rate: 1/9
Bore & Barrel Lining: Chrome molly
Barrel Coating: Manganese phosphate
Gas System: Rifle length direct impingement
Q: Will this work with my upper receiver?
A: The barrel will work with any mil-spec upper receiver. If you have a left hand upper receiver, please make sure to purchase the barrel with an ambi barrel extension to ensure the bolt will properly lock into the barrel extension.
Q: Do you provide instructions on how to install the barrel?
A: Unfortunately we don't provide directions on how to install a barrel and recommend that it be installed by a gunsmith to prevent damage to the rifle.
Q: Do I have to purchase a matched bolt to my barrel?
A: With AR-15's as long as you are using the proper bolt for the caliber you do not need to match a bolt to the barrel.