It truly depends on your tastes and the game hunted.

Most folks would use some variant of the Mauser action with CRF(controlled round feeding).They would avoid push feed bolts.

I would personally avoid any type of push feed action due to shooter reliablity issues with concerns of the shooter "short stroking" the action under stress and rendering the rifle useless. This could be fatal in a DG scenario.

For the heat of Africa and Buff/Ele a large BRNO 602 action or similar CZ action can be employed for the 416 Rigby class of cartridges.The Ruger equivilent, a investment cast type action,(not forged)is an option as well. Other smaller action sizes usually can be used from 375 to 458 diameter projectiles depending on shooter preference.

As for the make of the rifle it is whatever your pocketbook can stand!!!!