Hi Everyone.
New to powdercoating, so I'll do my best to describe the issue I'm having.
It's not residue, or fouling. After running a dry patch through the bore, it's mirror shiny. However, from the side I notice the bore is discolored. I noticed it's the same color as the smoke fouling on the muzzle of the gun after firing. It looks perfectly clean unless you look at it from the side, but there's no visible deposit anywhere..
I can't get this stuff off, tried Ed's Red, chore boy, and even Hoppes 9 with copper fouling remover. Scrubbed at it for a while too with no luck.
I'm using HF red, letting it coat in a dry tumbler, baking at 20 minutes at 400 (havent measured to confirm, but I see the powdercoating melting, and all rounds have passed the smash test easily) and dumping into cold water to regain some hardness.
Because I wasn't sure, I gave them a second bake, for another 20 minutes, at 420 this time, so I was confident the powdercoating was correctly baked on.
Load is 3.4gr Titegroup with a no lube groove 142gr boolit.
My best guess is the TG burns too hot, and hot gas deposits some of the powdercoating onto the barrel? It's consistent, super thin, resistant to solvents, and doesn't follow the rifling.
Suggestions?