Looks like great fun! But make sure you look into the 500MDM (500cal on basic full-length Ruger brass) plus the 500B&M (50 on a shortened RUM), and the 50B&M super-short for WSSM actions. There's also load data for these floating on the internet, plus all are contained in the QuickLoad database for those doing load development using QuickLoad.
Cheers...
Con