I'm pretty anal about barrel cleaning and clean them more than I really should. I think it depends on the gun itself, my handguns I always clean after shooting, shotguns same thing. Most of our rifles I don't shoot all of mine so I won't let them sit dirty it could be years before I get to shoot these specific rifles again. The rifles I do shoot on a somewhat regular basis in testing or if they are new rifles needing rounds down the barrel to smooth them out a little i'll clean after each use. Proven rifles I plan on hunting or just playing with during the year I won't clean until they get really dirty (no specific round count), then I will get every bit of fouling out including copper. I rarely clean a barrel before a hunt and if I do I will fire a few fouling rounds down the barrel and let it sit until the hunt comes. Most of the time I'll let the chemicals do their job loosening the copper, depending upon gun (known heavier copper fouling guns) I will run swabs of JB paste & JB bore bright down the bore then confirm copper is completely out with BTE or Ammonia based cleaners. I do use KG 12 as a copper remover even though it's harder to use and needs Ammonia based or BTE to validate copper is complete out. KG- 12 actually eats copper so it's a must to follow directions, and that goes for all chemical bore cleaners as not to damage rifle barrels and blueing. There are times when I will take a 100 % copper scrub pad, cut little sections of the pad with it's sharp edges and wrap a slightly undersized bronze brush to hasten lead removal from barrels, I have done the same for copper removal but I'm way more careful in rifle barrels (they do make copper coated steel scrub pads never use this type ). NEVER NEVER will I use any stainless brush in any barrel, Revolver stainless steel cylinder brushes I do use sparingly but only in the revolvers cylinder, never in an automatic or single shot.