Brand new shilen barrel on a custom build (not a savage). Barrel had never been fired. I shot 20 rounds through it and noticed a tight spot when cleaning it about mid way through the barrel, between 10-11 inches from the breech.
I use my lyman bore cam to see what is going on and I find this:






















This area is only about 1-2 inches long. The rest of the bore looks fine/has no copper. I have been using foaming bore cleaner, sweets 762, and some VFG pellets with JB bore paste on them. Nothing seems to be doing anything to this thick galling. I have never had a bore with copper in it as thick as this, especially after only 20 rounds! Any time I have had copper in a bore, a quick treatment with JB bore paste cleaned it right out in no time. This stuff is on there so thick, I am at a loss of what to do with it. You can feel this spot when pushing a patch down the bore with a cleaning rod. It feels like "rough" or "slightly tight" spot in the bore because the buildup is so thick.
Was shooting factory ammo (S&B), so it was not a super hot handload or anything.
I am at a loss as to why this would happen, and how to remove it.