Check out mould #356 and #357 from NEI Hand Tools, you can view their catalog online, just Google them. #356 is a .475 420 gr WFN and #357 is a .475 truncated cone. Both moulds are shown as plane base, but any of the moulds they list can be cut for a gas check. I don't know how available .475 gas checks will be though. PM Ben Hunchak for his thoughts concerning .475 cast bullets. If you don't want to cast your own Ben's the guy to talk to.