Re: which powders
My pet load for my 300wsm was 210 berger behind 60 gr h4350 210m primer Win brass. It was not the fastest load but by far the most consistent for my rifle. If my memory is still there I was getting just shy of 2800 on an 80 deg day and around 2675 at around 20 deg. If you want more speed and temp stable I would look at H4831sc, H1000, or Retumbo I was able to get 2900 fps with these powders from a 26 tube. Most were at pressure limits and none of them were as concistant with my rifle. Another issue you may have is finding any of the powders listed here. Good luck.