I would back the R22 load down a little and work the R19 load up to about 66grn. Both should give you around 3300fps. Both powders appear to be capable of grouping in your rifle. With shots over 300yds, a load with low ES and SD will benefit you more than that last 150fps ever will.

My rifle happens to like Magpro and the 140gr Accubond. I chose it over the 130's because I am actually gaining by using the heavier, higher B.C bullet at the same relative velocity as the 130's. The load I shoot is 72.5gr and averages 3260fps with a nice low SD.

This is God's universe, and he has a plan. You might think that you have aa better plan, but you don't have a universe.