It appears to me that some here are not getting their bores really clean. After cleaning, you can run a patch through my bore, and it comes out snow white, I use a bore brush. If I did not, the patch would come out dirty, not to mention copper build up. Try this, run a patch with solvent on it through your bore, let the solvent sit for 15 minutes or so. Then run a patch through, see the greenish blue, that is copper. brushing will help to remove that and powder residue just patches or a bore snake will not.