CMC Triggers AR-15 Barrel design is the perfect addition to your SBR or Pistol build! You do not want your SBR or Pistol barrel to be too light or too heavy, so the CMC Barrels AR15 Barrel is your solution! CMC's AR15 Barrels are made from 4150 Chrome Moly Vanadium, coated in H&M Blacknitride+ for increased wear resistance, chambered in .223 Wylde so that you can feed it both .223 and 5.56 NATO ammo. CMC incorporated input received from military, law enforcement and civilian shooters into the engineering of their AR15 barrels to accommodate modern-day shooting requirements. Every barrel is precision, instrument-inspected for absolute straightness and air gauged for maximum uniformity, yielding the highest accuracy possible. Land and groove tolerance from breech to muzzle can vary only .0001" for the best concentricity. With M4 feed ramps for reliability, a 1:7a ^2 twist rate, 1/2a ^2x28 thread pattern to fit standard AR-15 muzzle devices, 11-degree match crown for increa...