You might want to stop doing that !!!!
By hand you can allow the tight fitting patch to follow the rifling twist the length of the barrel, say only one turn in ten inches of barrel length, then reverse the rod without it ever exiting the muzzle end. (The muzzle end of a barrel often has two tenths of a thou constriction to give best accuracy, vigorous 'cleaning' there may remove it.) This allows whatever compound you are using to clean all the detailed surfaces of your bore/rifling.
Higher rpm in a drill will just wear the top of the lands down without cleaning up the deeper groove areas, which often hold the most copper.
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