Sauer14,
I been on the same quest for a good while! Now,with a ruff time finding powders, I have tried to adjust the loads to the Temp. Ball powder seems to be too hard to be consistent.
I've had the best results with stick powder,like H-4895,Varget,IMR-4064 and IMR-4895. In my 30-06's, the 4895's seem most dependable! In my 308"s,the Imr-4064 is all i load.
I am in Pa. and the temps really are up and down. I don't load for maximum velocity,but i do load for consistent groups. I do keep a record of temps and the group sizes for each rifle.
IMHO,different primers,in different Temps,can be a variable?