I don't think I would have used the power drill in a rifled barrel. I would think any kind of polish like that you don't want to rub it across the rifleing, instead you want to push the thing in and out in line with the rifleing. You may have rounded off the edges of the rifleing and that might effect the accuracy of the barrel. In and out is ok but round and round could be bad. Hope you didn't hurt your gun.