Why not a 470 Capstick? You can buy commercial ammunition (it is pricey) as well as correctly head stamped brass. Hits a tad harder than a 458 Lott, 375 H&H length action. There was a gorgeous Model 70 "Big 5" in 470 Capstick at Cabelas awhile ago
-------------------- "There's a saying in prize fighting: Everyone's got a plan until they get hit"