Re: .243 AI
OK, I went the other way. 1 in 14 twist for high velocity 55s with some very impressive groups. I figured that a .243AI with heavy bullets is, well, a 25-06! I've got one of those and it works great on deer and antelope. I varmint hunt with it for the most part, although, on a whim I loaded up some 87gr Barnes XLCs for it this year and dropped a goat with it. The low recoil and deadly accuracy makes it very fun to shoot. Get a gauge to check for case head separation in your fire formed cases, if you don't have everything just right, all that brass you've got will only be useful to the local recycling center!
All it takes is One Good Shot!