The only problem with the savage is it take 150+ rounds after I clean it for the groups to tighten back up. The the accuracy lasts for few hundred rounds after that.
Is that a typo?
I'm a believer in keeping metal fouling well under control and I'm okay with with firing three to ten or twelve shots to bring the bore back in, but that's beyond reason.
Have you tried other bullets just to see about their metal fouling properties? Beyond that, I think I'd look at various chemical bore treatments (can't recall the name of any of them though...never used any).