Enjoy a Blast from the Past with these Phosphate Coated and Chrome-Lined Barrels.Great for cloners and purists, these barrels share the same features as our Bloodline 16" USASOC barrel with 5.56 NATO chamber and mid-length gas but with the classic, time-tested, and proven mil-spec phosphate coating and chrome-lined bore.Barrel Length16Barrel Weight29.97 OzBarrel Material4150 CMVBarrel Caliber5.56Barrel ProfileSocomTwist1/7Barrel Thread1/2 x 28Gas Block Size.750Gas System LengthMid-LengthBarrel Crown11 DegreeBarrel FinishPhosphateBarrel Extension FinishPhosphate