RL33 might be too slow for the 250s. Or maybe not! As far as data goes I'd start around 110 grains and stop when you can't cram any more powder into the case. Max load with the Berger 300s is 118 grains in my gun, which is compressed quite a bit.
I found good accuracy using 107 grains of H1000 behind a 250 grain Accubond in my rifle. Seated to 3.800". This is a few grains below max load but its very consistent, easy on brass, and gives me just under 3k fps.
From what I've heard RL33 is just as temp sensitive, I did just get 8lbs for my 338 edge, but plan on running that with 300 grainers.Thanks for the info. The H1000 might be what I end up with. I have been using rl25 which works good but am just wanting to try something different that might be less temperature sensitive.
I haven't tried any 300's I might. My barrel is a 1 in 11 twist so I was thinking it would probably like the lighter bullets better.For the big WBY case I would get some Berger 300s to get increased down range energy and wind performance then run it up to pressure with N570 (if you can find some) or RL33. Either will work well.
The stability will depend on your elevation. If you're above 2500 ft above sea level you're golden with your 11 twist. You'll give up a little BC if you go below that.I haven't tried any 300's I might. My barrel is a 1 in 11 twist so I was thinking it would probably like the lighter bullets better.