I just got a new barrel on a Stevens action. It is a select match grade barrel that has been hand lapped ( think smooth bore). I got it some what centered after 3 shots, but my groups were poor - over an inch. I was cleaning after every shot for the first 5 shots, then after every five. Poor groups. I then shot a five shot group from a clean barrel, but I did not clean for the next two five shot groups. The first group was about .3 inches with a flier out about 3/4", I know it was my fault. the next group was about the same with one flier out about .4" or so, which again I think was my fault. I am thinking it likes a dirty barrel. How dirty does it get before I have to clean?, I honestly do not know. Every gun I have had shoots better from a dirty barrel including my Handi's with the exception of a .223 with a A&B brrel, it seems to like a clean barrel. I had a 222 Rem in a Remington 700 BDL VS that absolutely hated a clean barrel. When I first got it, it shot horribly. I had traded in a Remington 788 in 222 for it and I was pretty upset about it. The 788 would shoot rings around the new fancy gun. I gave up on it and just started to shoot it. I had over 300 rounds down the tube and it was still shooting under.3 three shot groups all the time. I then felt guilty about it and cleaned it up real good - I could not hit a 1" group to save my self. Needless to say I never cleaned it again and didn't until it needed to be replaced because I finally shot it out. I think every gun is a thing unto itself, you just have to find out what it likes. I would shoot it until accuracy starts to drop off, then clean it. Good Luck and Good Shooting.