I was told by a gunsmith to take a swab and plug one end of the barrel fill the barrel with
sweets 7.62 then plug the other end of the barrel with a swab and let it sit for 1 hour!! He said dont let it sit in the barrel for any longer,1 hour is plenty of time for it to loosen all the copper out of the riflings then clean it well with a brush and then patches until all the blue color is gone then put your favorite protecting oil in it then your done. hello