hopdoc

What Marrakai says about above 2300fps definately has some basis in fact - although I think the magic MV figure is 2400fps which probably equates to 2300 at the animal.

I will say that a .510 inch bullet from a 500 cal definately shows an effect when hit - I have seen on numerous occasions the "ripples" going down the body of Buff when when hit.
I haven't seen this on +40 cals, sub 50 cal - 404, 416 (and to an extent 470).
As to how quick they die, alot of other factors come into play - where you hit them, how full the heart is, whether you hit or clip the spinl cord, etc etc.
I shoot a 500 well so that is what I use but I would be comfortable with 404, 416 etc.
I will say that I see people with 416's and they aren't as nice to shoot - too fast a recoil - I prefer a long hard shove to the short sharp crack of a 416.
500 Nitro