Hi,
Since I have only been deer hunting 6 years I cannot be the voice of experience.
BUT is is a slow day at work so heres my $.02 worth...
My father-in-law generally puts the cross hairs in the center of the chest. His .35 rem has stopped a considerabe number of deer, and I have seen at least two dead deer that he hit while the deer were running.
Consider terrain, his shots are all Wisconsin forest, 125 yards is a very long shot. (mostly you cannot see farther than that) This also explains why .35 rem has been a very good choice for him. (it is his first, and so far, only centerfire rifle.)
This year I hit a deer at about 175 yards, I aimed for the center of the chest with my .30-06, and took the bottom of the heart out. (it looked like a 4 or 5 leaf clover)
That deer ran about 35 yards in the picked corn field before he stopped, dropped and rolled. (but didn't get up)
The next day a fawn stepped into the field I was in about 55 yards away from me(quartering to me). Put his head down, and I aimed for the offside front leg, in the center of mass. I hit the nearside shoulder socket, I KNOW this because when I cleaned the meat I had a ball on the leg bone, but fragments where the socket had been. I spent the better part of an hour picking bone fragments (carefully) out of the surrounding meat. The analysis I did as I was deboning (the fawn shoulder)looked like the bullet left a .308 hole thru the meat to the shoulder, then apparently a bomb went off, from the near shoulder to the +1" exit hole in the far ribs there was a lot of damage. (assumed thru lungs, but I verified at the site that the heart had a 2" split in the bottom) He fell RIGHT THERE and didn't get up. (THIS WAS 1 SHOULDER SHOT OUT, not both!)
I also shot a doe with my shotgun and slug. First shot was 115 yards at a standing broadside deer,(paced off after) MISSED. (Hmmm, wonder why?) The deer started running and I, not knowing if I had wounded it, made a second shot at about 80 yards which connected in the middle of her neck (and went right thru the windpipe etc.). She was running in a picked soybean field, I knew not to lead too much, but I had the front bead between her ears and neck as a lead to the chest... and the shot went thru the middle of her neck. Dramatic results. (can you follow a 3" blood trail in an open field if it is 36" wide?)
Given that I wanted a chest shot, I thanked the Lord for my nice fat doe. I don't think I would aim for the neck (especially with a shotgun with slugs) because it moves WAY too much.
For beginners,
I think standing broadside center of chest at a standing deer is what you wait for.
I think next, that standing chest shots, if not going to get "Perfect" broadside, should be aim for far side leg. (best chance to hit vitals.)
I also think telling a beginner to keep shooting until the deer stops moving is NOT recommended. (although some people with lots of experience actually do just that for some reason.)
Shoulder shots do stop a deer right there, but unless that is necessary, I wouldn't recommend that as preferred POA to a beginner. In the boiler room is what I would suggest.
as always YMMV, and IMHO.
Gfrey