I haven't seen much data on the .500 s&w but would go along with any of the pistol data you could find as far as reduced loads. It sounds like an interesting project. I know the .500 handi has a reputation as a real thumper as far as recoil goes. I have a 45-70 handi which is easy to find a lot of reduced load data and there is a great amount of bullet choices around. A 350 gr. cast bullet at around 1300fps is kitten to shoot whereas a 410gr jacketed of heat treated lead at 1700fps is getting close to being not much fun. The .500 promises to be an interesting new cartridge that is just starting to be chambered in rifles. Good luck and have fun
I'm not so much looking for a low power load as I am a low velocity load. I'm not concerned with the amount of recoil at all. I want to suppress it, but I also want as much punch as possible. So I guess what Im looking for is a load going at roughly 1000fps with the heaviest bullet possible without going over a safe chamber pressure.
Have you shot it yet???? and what is heavy???? I can tell you where you can get some excellant 700 gr. bullets but even sub-sonic they would be a killer, on both ends, in a Handy Rifle. I think all of the powder manufacture have data for the 500 S&W on their web page, this is data you can trust. You can also check out www.handloads.org, but alot of this data was not presure tested. You should have no problems if you stay with bottom end loads and since your looking for sub-sonic. If you need more data PM me and I`ll PM you some.