I have had great luck using IMR 4064, 34.5 grains with hornady 55gr sp. Very Accurate and great bullet performance, I plan to try 55gr vmax in the near future.

I've been reloading 22-250 for years. My best load is not necessarily the fastest but is the most accurate one in my rifle. I use 36.0 grns of H-380 and Hornady 52 grn BTHP Match bullets. These HP's are absolutely devasting on a prairie dog. The other thing to consider is your OAL, I have a Stoney Point OAL case length gauge so that I know my distance to the lands. I seat back about .005" off the lands which I believe gives me the accuracy. Use caution however when seating out near the lands so that you do not create excessive chamber pressures. Pick up one of the books by Rick Jamison, the 22-250 is his favorite round.

Tom