Every barrel was designed to optimize the original role for this caliber; to be suppressor friendly and accurate. It is Rosco's goal to get you the performance that you seek out of these barrels when running sub-sonic ammo or supersonic ammo (depending on barrel length). Twist rates, gas port diameters, and lengths have all been taken into account when we set out to make these. Let's just say that we don't like leaving things to chance.