This post is dying fast. Tell ya what. Use whatever rifle/gun/bullet/sheel combo you want. If you do your part and be an ETHICAL hunter, your game will not go far at all. I never shoot at "running full speed" deer. That is ridiculous. (read from another post) I rarely shoot anything that is moving. But that is just me. I like taking my time for the best shot. You don't HAVE to kill something everytime you go out. That's not hunting. It's shooting. That is also another topic for another time.
I want someone to guess which rifle/gun/bullet/shell this deer was taken with. As a bonus, guess the yardage. Then stop talking about "the best" for combination for skinny little whitetail deer. They are not tough at all. By the way, that is the entrance wound. Perfect heart shot. I like the animal to absorb all of the energy. Hydrostatic shock kills. You don't need two holes for blood unless you are bow hunting, and even then any good broad head will empty a deer quickly with just an entrance hole. Animals die from blood loss with arrows, not shock. Yet another topic for another time. Keep it simple.