Nickel plated jags and BoreTech Eliminator or BoreTech CU+2. Nylon brushes for the stubborn spots.
That is the answer. I Tested Shooters Choice, a couple Hoppies products, CR10, Sweets 7.62, Montana Extreme, and others. All said the bore was clean but when I went back in with BoreTech I always got more copper out.
BoreTech, 3 or 4 wet patches, wait 10 minutes, and 3 or 4 more wet patches, repeat until all blue lines are off the patches completely. It takes time, but once you get it truly clean the next bullets will work to lap in those rough areas that are grabbing the copper. If you don't clean all the copper off the rough spots it will never lap in.
Jeff