Had good results with IMR7828 in both 300's with 180-200gr bullets. However I mayopt for the IMR7828SSCwith thewsm as it will allow you a little more case room. The H4831SC would also be a good one to try.

Personally I like RL22 but not sure how it will perform in the short mag, I know it works well in the 7mm rem mag and 300wm though.