Re: 208 gr Amax and 210 Berger load in 300Win Mag
I did not have good luck with AA Mag-Pro. IMR7828ssc, H1000, h4831sc would be my absolute top 3, with H1000 being my first and foremost go-to powder. Use Win LR primers and Win Brass and you are gtg. You could also use Fed 215m primers I suppose, but I would only contemplate them if you are planning to go shooting in the interior of Alaska in winter or something. The Win LR primers are a fairly hot primer, thus they generally work quite well in the "Lesser" magnums like the 300wm. If you are not using over 90gr powder, the Win LR should be more than adequate.
Have a good one