This barrel is for the M11/NINE 9mm. It is the standard length with standard threads of 3/4-10 TPI. It is made of CrMoV MIL-B-11595 material with 6 – groove, 1:10 twist and precision air gauged with inert gas vacuum stress relieved after button rifling process. The finishing is manganese phosphate, the traditional dark gray/almost black parkerizing of the MAC series guns . These were profiled on centers to provide accuracy between bore and profile which has been a problem we’ve experienced with other manufacturers’ barrels in the past. These will fit Full and Semi Auto M11/NINE 9mm guns.