Turtle
Try VV-N150, H380 and H4350. I would suggest the VV-N150, it's awesome powder. Here is load for you to try;
1. Lapua brass
2. Federal 210M Primers
3. 45grns VV-N150-Work up to this, so start out with 43grns and work up to 45grns.
4. 75grn V-Max
Try the 87grn V-Max too, it's a great bullet. Try this load;
1. Lapua Brass
2. 46grns H4350-Work up to 46grns.
3. Federal 210M Primers
4. 87grn V-Max
If you have a 28" to 30" barrel, you should be able to push the 75grn V-Max to around 3700fps. My buddy uses a 6mmAI with 30" 1-10 twist barrel. He pushes the 75grn V-Max at around 3800 to 3850. The 75grn V-Max is absolutely devastating on Squirrels, Groundhogs and PDogs.
I either use Ballistic Tip's our V-Max bullets for my varminting. They work well out to around 800 yards. I love pushing a Ballistic Tip or V-Max bullet at super high velocities. The splat factor is awesome!
The 243AI is an awesome varmint cartridge. Have fun with it and let us know how the load developement works.
W.