ArmaLite's barrels are custom-made for extreme accuracy and long life. This complete barrel assembly includes a Picatinny rail gas block, barrel nut, slip ring, slip ring spring, slip ring retaining ring, gas tube and handguard cap. Post-Ban configuration includes recoil check.
.750 at the journal (under the gas block)
Caliber: .223/5.56 X 45 mm NATO
Barrel: 20" Chrome Lined\Chrome Moly Vanadium MIL-B-11595-E, M-4 Feed Ramps
Rifling Twist: 1:9"
Muzzle Device: Permanentley afixed Muzzle Brake
Finish: Manganese Phosphated Steel