There are hundreds of variable that affect accuracy. That' s one of the neat things about reloading. I always start out with 1/2 grain increments. Once I find one or two loads that group well, then I begin experimenting with bullet seating. The other variables have to be the same(case prep, primers, etc.). I personally love the 7mm mag. By the way, the best accuracy I was able to get with H4831 was 5/8" . RL-22 behind Sierra 140 btsp' s achieved 1/4" groups. Of course, I' m shooting a Rem 700bdl, not a Ruger #1.