With what you describe (and what you're evidently going to have to live with) I strongly recommend Dave Tubbs' Final Finish bore smoothing system -- 10 bullets each with five increasing finer grit surface coatings. If you've used it before, you know what it does -- dramatically decrease fouling (especially jacket fouling) and increase velocity (~60-80fps) at slightly lower pressures. Accuracy/consistency is noticeably improved in "average" commercial barrels, and moderately in "excellent" (e.g. Krieger) barrels.
After using it in three different rifles (HBAR, Garand, Krieger 300WinMag) Tubbs’ system has always performed as advertised (for me). If might give you some extra breathing space.
