The current owners of CH4D were selling old stock from the previous owners for many years. Sales were relatively slow for a long time, but have picked up in the last couple of years because people want to become more self sufficient during shortages.
When they sold out of the popular calibers, they made an attempt at making a good size run of .44 caliber swaging dies, but when they sent them for heat treating, they all warped. They made the business decision to put their efforts into dies that they sell a lot of, so they discontinued the swaging dies altogether. It's unknown if they'll make them again sometime in the future.
Hope this helps.
Fred