Folks have all kinds of opinions about where you should shoot a game animal and what should happen after you shoot it. Personally, I think we've done a grave disservice to newer hunters by letting them think a deer (or any other game animal) should be Dead Right There at the shot. I'm a confirmed heart/lung shooter. Animals shot through the boiler room almost always run a ways--perhaps up to a hundred yards, but more commonly half that distance. I'm also probably the most bungling woodsman on the planet. I have no sense of direction and I'm color blind. Still, I've never lost a deer shot through the heart/lungs. I just watch the general direction in which they run and follow after them. It ain't rocket science. Put a .30-30 bullet (150 or 170 gr.--your choice) through the boiler room of any deer (reasonable range assumed) and it won't go far.
Disclaimer: I don't hunt where hunters outnumber deer (so I'm not worried about someone else claiming a deer I've shot first) AND I don't have to worry about looking for downed deer in poisonous snake country. Perhaps those two realities would change my "shot placement" philosophy.
PC