The .22-250 AI is a better mousetrap than the .223 WSSM, IMO. I think you are on the right track . . . . .22-250 AI with a 9" twist (or 8") and a 26" barrel. The 75 A-Max would be my bullet of choice, and it works well in a 9" twist - but if the barrel doesn't like that bullet (and you never know), then an 8" twist would allow you to experiment with heavier projectiles. ALso, get a stainless steel barrel if you can afford it. They will last a little better on the more overbore calibers. Good luck.