People who scoff at the 500 Mag simply don't have a clue. I've been shooting them regularly since S&W started selling them in 2003.
If you seat slugs out to full cylinder length as John Ross does, energy figures can go into the 3200ft lb range out of the 8 3/8th" barrel.
With hard cast slugs they will equal or highly likely exceed a .375 H&H Mag in penetration.
While it is not a scientific test by any means, I've shot a .308 Win and the 500 side by side on water filled gallon milk jugs. The .308 with JSPs sort of bounces them around. The 500 simply DETONATES them into a huge ball of spray, makes the .308 look puny and on large game is far superior. Don