I've spent a good deal of $$$ on custom barrels for several of my .22RF rifles, and I wipe them out after every range session, using good quality rod guides and rods. Have seldom seen the need to use a bronze brush, though I do occasionally use a nylon brush when breaking in a newly chambered bbl if I feel any unusual resistance while pushing a wet patch through the bore. If I haven't polished the leade in such a barrel, it will sometimes cause a little leading, but it doesn't happen all that often, and never seems to happen again after the first 50 or so rounds. Never really seen the need to use anything stronger than Ed's Red, which is a mix of equal parts of dexron-II ATF, kerosene, mineral spirits, and acetone. It has to be stored in a glass container because of the acetone, but I'm still using a 1/2 gal apple cider jug that I mixed up about 10yrs ago to refill a smaller glass container that I use on the cleaning bench.
I've read & heard all the opinions about not cleaning until accuracy drops off, and just don't see why anyone would treat a good rifle that way - whether it's a .22RF or any other chambering. I recently cleaned a V-22 repeater for a friend who'done just that - shot it until the accuracy dropped off. I borescoped it after putting a few wet patches through the bore, and decided it needed brushing due to not finding the bore as smooth as I'd hoped it would be. Even after brushing, I was seeing something that looked like fine pits in the bore - and this was a custom stainless bbl. Hope his barrel isn't ruined, but I've never seen anything quite like what I saw in his barrel in any of my stainless custom barrels, so don't know whether it was caused by lack of cleaning or ??? I bought a nice new Rem 541T back in 1993, and found that it shot really well with a lot# of WW Super-X hi vel copper washed HP. I cleaned it fairly regularly, but after the POS plastic mags I had for it crapped-out on me, I must've been disgusted with it, and put it in the closet w/o cleaning, where it stayed until I bought a couple of John Reed's beautiful SS 5rd mags. Got it out and took it to shoot on paper at 50yds with its favored lot of Super-X, but accuracy had dropped off quite a lot. Cleaned the bore thoroughly, wiped it dry, and borescoped - it looked somewhat rough, like perhaps the chromemoly barrel had developed some pits from being stored fouled. I'm in western Kansas, and we typically have pretty low humidity, but it looks to me as though I'm going to wind up re-barreling this rifle if I expect decent accuracy out of it again...