this cast bullet is both accurate and very lethal in a 500 mag revolver over 20 grains of BLUE DOT POWDER velocity is about 1169 fps, certainly not a max load
heres a source for required gas checks
I use mag pistol primers https://www.sagesoutdoors.com/500-s-w-caliber-gator-gas-checks/ in my friends 7.5" S&W revolver which is proving to be very accurate, and I would hunt anything in north America with it loaded like that