Nothing much to add really, other than the observation that a few thou of copper on the lands towards the muzzle of a high-velocity small-calibre target barrel is a far greater percentage of the bore diameter than the same few thou of copper in a .470 or .500.

I used to get excited about removing visible copper from the lands of my doubles, but now only give them the Wipe-Out treatment when the copper becomes super-obvious.
Usually the routine nitro-solvent dissolves enough copper each time to keep it in check. Then with a bore coating of Sweets Oil there is no corrosion under the remaining copper while in the gun-safe between hunts, and like Mauser says, the best oils continue to knock out residual copper to some degree during storage anyway.

I still like a plastic-coated rod with nylon bristle brushes, but I'm certainly not manic in its application. Been doing this all my life: absolutely no risk of bore damage IMHO if you're careful and conservative.

Hope this is of some use.