Hey Mike
Having the BFR I use Starline 500 S&W brass, I made a simple jig that allows me to cut the cases down on my high-speed arrow cut off saw. I finish them up with my case trimmer. I have sent a couple of requests to Starline over the past coupe of years asking they add 500 JRH to their offering. You never know ? If you don?t ask then you don?t get?
As for loads I have not worked with anything heavier than the Hornady 350 XTP. That said, the load I setup for hunting is the Swift 325 AF powered by Accurate #9 and CCI-350 primers this averages 1528fs. I had also good results with VV-N110 might be one to consider.
Good luck with your load development.
D?