I would suggest it would take a VERY modern SxS action to handle the S&W .500, however, factory ammo is actually loaded below it's maximum working pressure.

"500 S&W Magnum has a maximum working pressure of 60,000 psi (4,100 bar). However, most factory ammunition is limited to 50,000 psi (3,400 bar) to help ease extraction of fired cases. The cylinders of the S&W Model 500 revolver are engineered to be capable of withstanding 50% over pressure."