I'm working on my "FAMILY MARTINI": All mathmatically proportioned to the original .577-450 case
Interesting, I too like shooting the old MHs. Never thought of wildcatting this one. The case can hold a tremendous amount of powder. The only issues I see is you need a 50 BMG press due to the MH's large case. Even worse, is the extreme scarcity of boxer primmed brass. I have reloaded 577/450 on a standard size press. I have to neck size only using a 480 Ruger dies to seat and crimp the bullet. A crude method but it works.