I've killed plety with double lung shots and they work great. But I shot a doe from the ground a couple years ago. It was a perfect heart shot. She had the muzzy X perfectly placed on her heart when I field dressed her. The blood trail was one a blind man could have followed. I could see blood on the ground 20 feet in front of me. She didn't go far either maybe 30 yards from the place I shot her.

If I were garanteed of a heart shot each and every time. That would be my choice. And if you miss the heart you still have the lungs. Of course that also why the slight quartered away shot is such a good, gets you away from that shoulder. I also wait for the deer to step forward with the legeffectivly gettingthe leg and shoulder as farforward as possible.

Simply put lack ofoxygen to the brainisthe waythey die. so heart or lungs and they are done.