generally higher velocity results in faster expansion,
more expansion results in a larger cross sectional area,
a larger cross sectional area results in more resistance too penetration,
this is partly off set by the higher impact velocity and energy,
keep in mind bullet construction and where on the anatomy the bullet strikes and how much bone it must penetrate, effects results
the higher the sectional density and the thicker the jacket the deeper the penetration tends to be.
if you value deep penetration select a bullet with a thicker jacket designed to slow expansion,
your 2000 fps bullets likely to punch deeper than the 3000 fps bullet impact
select the heaviest bullet with the thickest jacket, your rifle shoots accurately to insure deep penetration
with a .250-.300 sectional density , push it as fast as you can, safely
and select a decent name brand bullet,
your other option, select a reasonably heavy hard cast bullet in the .375 caliber to .500, caliber in that .250-.300 sectional density , and push it to 1800 fps-2100 fps
https://www.beartoothbullets.com/res...hp/density.htm
use a hard cast bullet of 400-480 grain weight in a 458 caliber like a 450 marlin,45/70 or down loaded 458 win
pushed to 1800 fps-1900 fps and you need not worry about a lack of penetration.
Id to be fair should point out that its a knowledge of the games anatomy and shot placement thats critical, and you don,t always need exit wounds to provide lethal damage, rapid expansion and deep penetration are both valuable traits, it only takes about 12"-18" of penetration in the correct spot to prove rapidly lethal, but an exit wound will tend to increase chances of a blood trail.

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http://www.neihandtools.com/catalog/index.html


http://www.rifleshootermag.com/edito...s-market/83865
you might find these worth reading
http://thebiggamehuntingblog.com/hunting-cape-buffalo-with-the-45-70-government/


http://www.ballistics101.com/images/bear_images/bearshotplacement.pdf