I wasn't aware of MFS making any brass cases?
I believe their line is steel cases with Berdan primers and they are practically non reloadable. If yours are brass cases and Boxer primed I believe they should take standard Large Rifle Primers like from Winchester, Federal, CCI, Remington etc.
I purchased some Prvi Partisan and Sellier and Bellot ammo with brass cases and have been reloading those with Large Rifle Boxer primers.