I really like Ramsnot Big Game as a powder for my AI. Specifically I use 40.3 grains under a 55gr Nosler BT. That is a relatively mild load only getting about 3750 fps. It will shoot into .5 in at 200 yd however, so I can live without it going any faster. That combo can flip a prairie poodle several feet into the air! Good luck with your AI.
Jim