I have a 24", 1 in 12" twist barrel chambered fro the 6mm PPC case. What is the heaviest bullet that will stabilize or shoot well in this barrel and/or what bullet weight would perform best in this twist rate?

You should be able to shoot bullets in the 80gr range, and they should give good performance. Anything heavier than that would be iffy for stabilization. Benchrest bullets in the 65 to 68 grain range should perform well also...

Thanks pointblank.....I was kind of thinking that it would be 80, 85 or 90...kind of hoping for 90 to 95. I still may try some at 90. thanks.