I've been in the habit of wiping RF crud out of the bores of my custom bbls after every range session. It makes no difference how many rounds I shoot, I'm not going to try to keep track of how many rounds I shoot through each rifle - just wipe them out when I get back into the shop. I use a fairly mild solvent - Ed's Red, which is a mix of kerosene, mineral spirits, Dexron III, and acetone. Two wet patches (using a rod guide), one dry patch, and 90% of the time, I'm done. If the 2nd wet patch still feels a little resistance/rough going through, I usually get a bronze bore brush out, give the bore a few passes, then another wet patch & dry patch, and that's it. So much easier & faster than cleaning copper & carbon fouling out of a CF bore...why wouldn't I do it?