Yes, if you buy the Forster lock rings, you are correct. However, from what I've read (I have never used a Co-Ax), the lock rings from other companies, including Hornady, work as well. In my case, I have changed most of my dies over to Hornady lock rings over the years just because I prefer them, so I'm already ahead of the game there. On the other hand, the FA die block is proprietary and only available through FA as far as I know.

I'm with you though...I don't see my Rockchucker IV wearing out any time soon, especially since I do my bulk loading on my Dillon and I have a Lee APP for the grunt work of processing pistol and .223 brass in volume.