I sometimes get the sense that my rimfire guns actually shoot a little better when the barrel is dirty, after the first few dozen rounds through. Anyone else experience this? I think I may recall a competitive target shooter mentioning this, as well, but I could be imagining it (Then again, it could be a real phenomenon and I could be imagining that I have the skill to detect when the gun is firing less accurately than I am. ) Does the lube build up in the barrel and tighten things up a bit? Even so, could there be any harm in leaving the barrel dirty, as several folks have posted? It was my understanding that lead and soot buildup would corrode metal eventually.
(just simul-posted with the above post, suggesting other people do see this effect)