The 458 Winchester has a poor reputation for penetration in Africa amongst most pro hunters. While it will easily go threw a buffalo side to side it lacks penetration on raking shots.

I have experienced excellent penetration with the big English cartridges for example my 475 # 2 Jeffrey @ 2150 fps which from my experience is about the minimum velocity for a projectile of about 500 grains. If you are serious about being able to deal with all potentials a 500 grain solid at no less than 2150 fps and ideally around 2300 fps, no more than about 2400 fps.

If you use heavier bullets you will require less velocity as momentum kicks in I have driven two 700 grain .50 caliber bullets *** to lungs on a charging (long story) jumbo at about 1850 fps.

Len