I hunted elephant, and hippo as well, with my .375 H&H magnum once and for such game, I reloaded this caliber with Cutting Edge Bullet Safari Solid 300 gr.
I used Vihtavuori N150 and my average muzzle velocity was 756 m/s (2480 f/s). It's easy with double base powders to push them faster, but I don't think it's really necessary for hunting.
Penetration was very impressive and in straight line.
When I made my load developement , this is the only bullet that passed through a big stump that I used to hold my target.
With quartering away shots, except one, all my bullets passed through the elephant chest and same thing for the one in the head with a side one shot. The bullet we recovered was the first one I shot and it broke the opposite humerus of the animal which was paralyzed. That's why I was able to shoot several rounds.