More info from the same document mentioned above........
"Certainly DO NOT ever use a stainless steel brush to clean out a barrel. The stainless bristles are much harder than the steel bore and the result will be to create deep scratches in the bore surface. When we use our IPSC pistols like sub-guns, as we often do, we apparently can raise the bore surface temperature up to the annealing range, based on the color I have seen on some barrel bore surfaces. Therefore, the bore surface of our barrels likely has been preferentially annealed, and could be quite a bit softer than the barrel outer surface would test. Even the brass/bronze brushes, which have bristles which are as hard as mild steel, or the lead removers, which use a hard brass mesh to scape the lead from the bore, may well be able to scatch the bore surface of a stainless steel barrel. Any scratching of the bore surface will naturally lead to increased bore surface wear, leading, and coppering. My recommendation would be to never use any kind of a bore brush to clean a 416 stainless steel pistol barrel, especially if it has been exposed to strings of rapid fire."