If they are still produced, RCBS will probably sell you one. A few years ago, I had an issue with one of my brand new .44 Mag dies. I ordered them from Midway, and the expander die had a chunk missing out of the bottom of it where it meets the shell holder. These are hardened carbide dies, so it was clearly caused during the manufacturing process. I called RCBS to see if it was still ok to use. Found out that it wasn't a big deal, but they insisted on sending me out a replacement one for free, even though I insisted it wasn't necessary. So, I thought that was really nice of them for going over the top on their customer service like that.
RCBS is a stand-up company in my book.