RE: When is it clean?
Just put 200 rounds through my hornet this weekend, it still shoots great. When I cleaned it with #9 hoppies it did have some green tinge to it at first and some copper dust too. After the patches came clean I oil the bore with kroil and let it set for an hour. Used more #9 and patches till it was clean and oiled it with kroil for storage.
Maybe some day I will buy a gun that just loads up and will be force to use harsh cleaner, but so far I have been fine forover 40years of shooting. I would argue that #9 doesremove copper just not cheimicaly but moremechanicly. You wont see blue copper oxide on the patches but that does not mean its not working.So don't be too fast to laugh at some one that doesn't have the copper issues you do they just might know something you don't. I have metalergiststo consualt with where I work and some are into shooting sports.