Gilbert,
I've used quality bronze bore brushes in all my custom 22RF barrels over the years, and have never had any reason to regret doing so. I don't use them often, as I wipe the bores of all the custom barrels after every range session - whether it's 10 shots or 100 or more - with patches wet with Ed's Red. I have several Vudoo rifles, repeaters as well as single shots, a Rem 40XB converted into a repeater to use V-22 mags, a RimX repeater, and a couple of CZ457s that I've re-barreled with Shilen ratchet bbls. I'm not about to try to keep track of how many rounds I've fired through each of those rifles, just clean them before putting them away. I can usually tell if there's any unusual fouling by the feel of the 1st patch through the bore, and if there's any doubt, an examination with a Hawkeye borescope will tell the tale. If there's some leading or carbon fouling, I don't hesitate to use a bronze bore brush wetted by Ed's Red. I don't need to brush these hand-lapped custom bores often - whether it's due to the regular cleaning I spoke of, or the quality of the bores' finish. OTOH, the bore of a used Win 52D that I bought last year seems to require brushing much more often, based both on the feel of the 1st patch and by what I see through the Hawkeye. It's got a good deal of reamer marks that the factory lapping only began to smooth out. As rough as this bore is when compared to the custom Bartlein, Benchmark, Broughton, Krieger, Lilja, and Shilen barrels on my other rifles, I'm not surprised. The other CMP-sourced 52D I have is a bit smoother, and doesn't seem to require brushing as often as this one, but they're neither as smooth as the bores of the two CMP 40XB rifles I've owned. Years ago, I traded a CMP H&R M12 to Mac Tilton for a nice used Anschutz 1611, and even though it had the blasted appearance on the lower half of the OEM bbl's bore from the throat to the muzzle, a simple wiping with wet patches usually cleaned it sufficiently to maintain accuracy.
I use a nylon brush occasionally in some of my 22RF rifles, and have nothing against them, but if I've got leading, I'm not going to mess around with a nylon brush - I'm going to put on a bronze one and git'r done.