I would use a "Ball Powder" but the way the weather here in Nebraska jumps around. (50's one day, triple digit another, in the middle of July.) I feel something more stable is needed.
Have you guys had any experience with 8208 XBR from IMR i hear its supposed to stay stable in almost all weather situations and velocitys compared to the grains is amazing. Somthing like 3925fps with just 36grs as a max load for a 50gr pill. They have a big write up on it in the new hogdons reloading magazine. I might be switching from H380 to this sweet powder.