In the .243 Win, my barrel maker suggested 1:9, though the Winchester standard is 1:10. I don't normally shoot 100 grain bullets, so it probably doesn't make much difference, but have shot Barnes TSX 85gr. and Hornady GMX 80s; it shoots them pretty well and they're fairly long bullets.
Regarding stabilization; bullet length is more critical than weight. That's why round-nosed bullet often shoot more accurately than pointed bullets of the same weight.
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