Any powder with a burn-rate from the 4350's to Ramshot Magnum is worth a try, whether H4831, RL-22, RL-25, H1000 or 7828. I've had my best luck with 100-grain bullets using Magnum in two .257 Weatherby's.
The reason Magnum doesn't appear as much as other powders when questions like this come up is because most handloaders stick to powders with easily available load data. Then they try a couple and stick to the one that works best in their rifle. But Ramshot will provide some guidelines if you ask them.
Even old IMR4350 often works well, as it should, since it's what Roy Weatherby used to develop the cartridge, since at the time it was the slowest burning powder available. As a matter of fact various Nosler manuals have listed as the most accurate powder with some bullets. Their newest #7 manual lists as among the fastest with 100-grain bullets, and as the most accurate with 110 AccuBonds.
If you hunt in widely varying temperatures you might also consider one of the more temp-resistant powders on the list.
