.375 Ruger brass is a whole lot cheaper and more available than 9.3x64. One quick pass into the die and it's formed. And I'd bet that custom 9.3-.375 Ruger dies wouldn't cost a whole lot more, if any more, than 9,3x64 dies.
Yes it's a wildcat, but for practical purposes the 9,3x64 might as well be in this country. It's not like you can buy ammo over the counter anywhere.
Besides...he
wants a wildcat...
.
Dennis