Just read an interesting article on this regarding actually shooting a .577 on elephant..an important item on the report was the velocity of the ammo used in 2 seperate cases on two bulls --the bullets failed to penetrate..later chronographed it was found the ammo was only traveling at 1800 fps...not enough, per the article, to penetrate the big bulls of Botswana..

Have had several PH'S tell me, again, for the big bulls as those in Botswana, 2300 fps is near ideal..

Based on the above, think the biggest gun one can handle and shoot accurately and provide the needed penetration is the way to go...have never felt a need to use anything bigger than my .416 but plan to use the .470 on my next ele hunt anyway...

Ripp