ORIGINAL: eldeguello
There isn't much room for improving rounds based on the .308 case. I see no reason that the 243 AI would need bullets much different from those you find in the regular .243 Win. Perhaps your quick twist will stabilize longer bullets, but they won't have any fantastic velocity advantage over the standard case with the same twist.
I now totally disagree with that statement. Bergers load data for the 105's max velocity was 2949fps. I just shot some out of my AI at 3401, 3406, and 3407.
450fps is a pretty big improvement imo...