Find some Big Game powder.
Put 47.5 grains in a case with a Winchester Large Rifle Magnum primer.
P
PS, I've never used Ramshot before, so was unaware BG was a ball powder. Given that the standard WLR was supposedly designed for the ball powders Winchester uses in their factory ammo, I'm curious why you opt for a WLRM. Just added security against a hangfire?