I got my barrel purchased today for the re-barrel on my 243, a 1 in 9 #4 Kreiger that will finish out at 24". I plan to shoot 85-90gr bullets through it for coyotes and a low recoil option for long range practice. Now for my next question, several people on other forums have said I should chamber it to 6mmAI to gain extra powder capacity. I did not know if it would be worth going to the AI in a 24" barrel or if I would gain much with that length. I would like to get 3300fps from the 90gr bullets, can I do that with the 6mm or should I go 6mmAI?