Lee makes a die set, I purchased mine from Epps, not sure who out your way would carry them, might have to get them ordered in or you can check the EE. Brass may be more of a challenge, Hornady made new brass and loaded ammo few years back, but finding it is a challenge, maybe try calling around and you might get lucky. Fiocchi sells new loaded ammo but the brass is thin and brittle by most accounts so not so good for reloading, although I can't speak firsthand to this. Also if your lucky you may be able to pick up some old commercial Dominion ammo in .455 at auction or a show and reload the brass. It's not so easy sourcing the rounds or components for these old guns, sorry I have no easy fix for your problem.