I guess if a deer were standing directly under my tree stand, I'd try a head/neck shot, only because he was too close to get a heart/double lunger. I agree with all the above. Shoot close, shoot big, fast, bullets. Put them in the heart and lungs and then pick up your deer.
We seem to have a preoccupation with trying to kill deer with the smallest bullet. Guys!!! think about it! Turn it around and kill deer with the largest bullet and work down from there. You don't want to use a 125 gr. SJHP in a .357 for deer.
Here we go!!!!! STOP!!! I know how many deer have been killed with itty bitty loads. My granddad killed probably a hundred deer with a .22 years ago when there were no regulations. Virtually any bullet will kill a deer. What we're talking about is a clean kill at reasonable range. Go for the heavy bullet, and hit "center of the mass"..heart, lungs.
If you were going to put him out with a heavy cast bullet, why wouldn,t you just shoot him with it to begin with, and save your pop gun load to put behind his ear if needed. Most likely not.