Perhaps a little different approach would get you the best results. I suggest that for long range accuracy is the most important componant to get that you need to pick a good bullet and sabot that will hold 2 inch groups at 100yds as for the powder load get loose powder and shoot groups with it every 10 gr untill the group opens up over two inches then lay your targets out in front of you it wont be hard to tell what load is best. Lee
Also sight in 2 inches high at 100yds and chek your drop at your max range when you find that best load, this has worked well for me with all mine.