If I was looking for a round that would make a wound channel I could drive through, and leave a blood trail that Stevie Wonder could track, I'd choose a 416 Rigby mag pushing 325-350 gr bullets ~2800 fps. Now I don't think most folks can shoot such a rig as accurately as a smaller one though.
Now back to reality, no amount of power makes up for poor shot placement, or allows you to take shots you shouldn't. A 30 cal will kill any NA game, every time, so long as you place the bullet where it needs to go. Bigger cals can break down more bone, and allow for more consistant blood trails, but they don't negate the most fundimental tenant of hunting which is, know where to put the bullet, and put the bullet there. If conditions are such that you can't make that happen, hold off.
