Too bad about the foulers.
I have an old Oberndorf Mauser 9.3x62 that fouls badly with about anything, but shoots OK. The bore shows neglect & was severely coppered-up when I bought the rifle in about 81 or 82.
It just takes a long time to clean it. I have to use Butches Bore Shine or Sweets in it. Foam-Out works better (overnight soak) than anything, though. Wipe Out is no better than the other cleaners noted, for me. Some guys like it. I have not found the accelerator actually worked any better than just using the solution.