I have only shot factory ammo through mine so far, I still need to get dies for it. You can check out 450bushmaster.net, that is currently the place to get info for the 450. The creater of the 45 Professional, which Bushmaster shortened to make the 450 posts over there as Wildcatter.
This site has a thread with the most extensive work on reloading the 450B I think you will ever find. I hope the link works, I am currently in Afghanistan and can't access the site. I am pasting the link from my favorites. If it doesn't work just search 450 Bushmaster. The last time I visited there were over 60 pages in the thread.
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