I dare say you are doing something incorrectly. I will give the barrel 25 full length strokes, a patch to push out loose fouling, repeat, patch, repeat then go after copper with patches. If you are referring to hard carbon in the end of the neck of the chamber or freebore I get that out with a one caliber oversized bronze brush on a chamber length rod. I push it into the beginning of the rifling while twisting and withdraw while twisting. After a few passes I can short stroke that area with the same brush. I wet the brushes with carbon cleaner du jour (I use Bore-Tech C4 but I don't think it has any advantages over the others). If the carbon is long standing you can get it out with the above then use an oversize nylon brush with a light coat of Iosso paste using the same motions. I have never had this approach fail; I confirm my cleanings/ evaluate the throat periodically with a Hawkeye.I have six dozen new bronze bristle brushes from Sinclair, still did not get the carbon out!
I will give the barrel 25 full length strokes, a patch to push out loose fouling, repeat, patch, repeat then go after copper with patches. If you are referring to hard carbon in the end of the neck of the chamber or freebore I get that out with a one caliber oversized bronze brush on a chamber length rod. I push it into the beginning of the rifling while twisting and withdraw while twisting. After a few passes I can short stroke that area with the same brush. I wet the brushes with carbon cleaner. . . .
It may not be a carbon surface deposit but metal discoloration or perhaps it is artifactual.
Help orient me.... I presume the end of the chamber neck is the very sharp dark line ahead of the case mouth in the lower picture?
Can you get a long 'needle tip' probe with a very short right angle at the end into that area. If you can you should be able to 'sound' it and determine if there is a raised carbon ring versus metal discoloration/shadowing artifact on the scope.
Robin
I have not tried Wynn's.Not really "gear" per se. Wasn't sure where to post it.
Has anyone tried using Wynn's GDI, PFI and EGR De-Carbon foam? Car dealer says it's good stuff. Don't know how well it would work with barrels. MSDS sounds nasty.
Anyone have any idea's?