The barrels are rough and inconsistent if you look down the barrel with a bore scope,however I break them in like a fine bench gun.I shoot one clean and repeat this through 15 rounds or so then shoot 2 and clean 5 times.Usually by then they will settle down and start to shoot decent.I would leave it filthy as the more you shoot it the harder the carbon gets. Then when and if you clean it,it becomes a real chore to get all the hardened carbon out of the barrel and throat of the barrel.Before I shoot any factory barrel I scrub with JB Bore paste to remove excess bluing and slight burrs in the rifling.