Stick with powders like IMR 4064, 4895, Win 748 (if you can find load data for it) and I think Win 760.
The gas system, while adjustable is suited to medium rate powders and basically powders suitable to the Garand and the M1A/M14 family (308,30-06) are safe for use with the proper load data.
You can always phone Sierra bullets and they can usually help you with questions like this or one of the larger powder makers, Accurate Arms, Hodgdon etc. and you can try the collector boards.
I was loading a similiar load, in military grade brass and while it safely functioned in the rifle and was accurate and had no pressure signs, I didn't have a scope mounted on the rifle so POA and POI were not very close.
I generally look for Mil ball and tear it down for the bullets and discard the case and powder with exception of certain types of ammunition, most of it is 198 grains.
Hope this helps