Um, that makes absolutely no sense whatsoever. Please explain how a fouled rifle barrel works better than a clean one. And I have never heard of a barrel getting ruined through repeated cleaning. Improper cleaning? Yes. But not repeated cleaning, especially if you are only running a cloth/mop through the barrel.
When I speak of a fouled barrel shooting better I’m talking about a barrel, most likely factory, that has had 5-50 rounds fired through it during a shooting string. Do I have scientific data to back up my claim? No. But I do have real world experience that guides my opinion. Naturally, you can probably find differing opinions if you searched the web.
Most factory barrels are not hand lapped and have a rough internal finish when compared to a hand lapped custom barrel. This is why some may try http://www.davidtubb.com/final-finish-loaded-ammo to correct this issue in hopes of improving accuracy.
Through a course of fire one may experience a stringing group followed by the group tightening up. This could be caused by shooter error, quality of ammo, improper bedding, or slight differences in pressure due to fouling. Determining the culprit is difficult but if the group tightens up the ammo is probably not the issue and if the shooter has good and consistent shooting form it’s probably not shooter error. That leaves only the bedding and the barrel. If I clean the snot out of the barrel and take it back to the range and still have stringing issues followed with the group tightening up chances are it’s not the bedding. That leaves only the barrel. Now, why are the groups tightening up after a few rounds of fire? Could it be due to a light copper/carbon fouling? To check this, I would not clean the barrel after the range trip and I would wait to see if it strings rounds on the next trip to the range. If it doesn’t, I would deduce the barrel shoots best with light fouling. Once the accuracy goes to crap again it would probably be due to a heavy fouling issue and I would need to give the barrel a good cleaning with the knowledge it needs a few fouling shots for best accuracy.
I agree with what PR-6284 said concerning barrel cleaning. How many can say they have a bore guide, proper cleaning rod/jag/brush, and correct size patches? If you are using chemicals/paste, are you mixing chemicals/paste or getting all the chemicals/paste out of the barrel before shooting it? Are you leaving the chemicals/paste in the barrel too long? Are you using a stainless brush or scrubbing the barrel? Are you dragging it back through the crown or cleaning it from the muzzle end? How do you know you got all the copper fouling out? Chances are most people who believe they have cleaned their barrels still have light copper fouling and just don’t know it.
Improper cleaning will damage a barrel quicker than we think. I use a bore guide, nylon brush, bore tech cleaning rod/jag, and proper size patches. I use bore tech cleaning products only and never use pastes. Most of the time I don’t use a brush while cleaning and I don’t clean until accuracy falls off. But my barrel is a hand lapped Bartlein (not factory) and doesn’t seem to have a copper fouling problem. My Tikka has two range trips with 70 total rounds through it without the barrel being cleaned and it still shoots sub ¼ moa at 100 yards with reloads. Last weekend I shot it out to 1050 yards with no problems.
As I stated in the beginning, this is only my opinion but it is based on what I have experienced in the past. Some barrels don't shoot worth a crap when their clean, dirty, dry, or wet