Free: Contests & Raffles.
If he can't fix it I would send it back to Howa.Nothing you did should have done anything even remotely like what you saw. You were using factory loads with the solvents you mentioned? Nothing else? It didn't get dropped in the ocean, shot old surplus ammo, fancy break in miracle homebrew solvent or anything like that?
Tagging as I bought one of these rifles a few weeks ago. I'll have to take a good look into the chamber when I get home. Hopefully you can get it cleaned up or Howa takes care of it. Good luck.
Great news! Good luck with your season!
Probably wasn't even pitted, just needed a good cleaning. Good luck on your hunt.