In short range Benchrest, most of us clean after every group. To my knowledge, we all use a bronze brush.
i don’t overclean my barrels. I follow Kriegers recommendations in that I am not interested in getting every smitten of the “wash” that you all see with your borescopes. Krieger says you should leave that in there on their cut rifled barrels. After two rounds, it’s back anyway.
we don’t shoot in competition with squeaky clean barrels.
Here is a true story.
At one of the Group Nationals some years back at Midland, a bunch of us were”sitting around the campfire” the night before the Light Varmint 100, discussing our various methods of cleaning. A very well know shooter produced a bore scope.
We all brought our rifles out so the borescope could tell the tale. When mine was examined, I was asked if I had cleaned it after the last match. I said yes, my usual regiment, many strokes with a bronze brush saturated with Butches Bore Shine. I then run as many wet patches through as it took for the patches to come out clean.
I was informed that my barrel had all sorts of stuff in it, at the very least I should scrub it with ISSO, JB, or what ever. It might be too far gone. Dead on arrival.
I said no, it was ready to go to the line.
I went out the next morning and won the yardage with a nice .162 agg.
I put nothing in my barrels but Butches Bore Shine. I use a bronze brush Religiously. I shoot only cut rifled barrels.
And I haven’t had my borescope out of it’s box in years.