The 20" 5.56 NATO barrel has a military A2 HBAR profile. The barrel has a 1/7 twist. The barrel extension is pre-installed and headspaced.
Caliber: 5.56 NATO | .223
Diameter at the gas port: .750"
Barrel Threading: 1/2x28
Twist Rate: 1/7
Barrel Profile: A2 Heavy Barrel (HBAR)
Barrel Material: 4150 CMV
Barrel Lining: Chrome Lined
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.
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.