I just picked up a 300 Win Mag and this topic is very timely. I was very surprised to see data in my manuals vary so much for some powders. H4831 in particular would have a starting load from one manual be close to the max load for another one. Recent data seemed to be more conservative if I remember correctly. I've got a 20yr old keg of IMR 4350, 8yr old can of H4350 and a brand new keg of H4831 SC and was leaning towards the latter with 180gr BT/Partitions. If I'm going to use it this season I need to take a guess at a good load that optimizes velocity without weeks worth of workup. Suggestions for any of these?
