I recently bought one each of these powders to try in my 300 win mag and my 6.5 x 47 lapua.
here is what i did, now im not saying that the way i did this is the right way but it seems to work for me.
IMR 7977 for the 300 win mag
norma 300 win mag brass w fed 215 primers and 208 A-max seated...