As an aside to the topic, about 35+ years ago revolvers in .455 were not popular, although fairly common and very inexpensive, mostly due to the lack of readily available ammunition. As they were so cheap I ended up with a couple of Webleys and an S&W.
There was a company, Mountain and Sowden Engineering, just outside Halifax, England (my home town), manufacturing new .455 Mk. II brass as well as other hand-gun and rifle brass, all boxer primed. It was excellent brass.
One trip back to visit my folks, I bought a couple of thousand rounds of .455 brass to bring back to Canada with me, and arranged for future shipments to me here as required, figuring there should be a market for it. Little did I know.
I advertised in The Gunrunner newspaper out of Lethbridge (remember that?) and in Shotgun News in the US of A, both with little to no response. I sold some through word-of-mouth, and at local gun shows, and kept a few hundred for my own use, but it was like selling ice to Eskimos, so once they were gone, that was it.
Fast-forward to 1997, after the draconian U.K. handgun ban, and Mountain and Sowden goes out of business.
Fast-forward again and there is some demand for the brass, but no ready supply of it.
That's life.