My mantra is that I want all the hunting to take place before the shot. I don't want to hunt for the animal after the shot. That being said, and lots of animals through the freezer, in all but two cases did I take anything other than a shoulder shot, Even on quartering away and quartering towards. I want them to stay in the spot that I last saw them. The two exceptions were on two huge antlered whitetails. Both walking away. One was fairly close and had walked out nearly under my stand. It was on a trail and was obvious it wasn't going to give me a look at its shoulder, So I aimed a the back of its neck a couple of inches from the skull. Instant kill. The other was walking away, again on a trail, getting ready to disappear into a thicket. I was shooting from a rest and aimed at the center of the butt. The bullet exited the front chest scrambling everything all the way through. Those two were my only exceptions.
On the subject of pigs. I raise pigs and regularly dispatch pigs in the 400 - 650 lb range. I've taken advantage of the opportunities to use many calibers and many points of aim. The most effective has been a 2 3/4" .410 slug between the eyes, following that a .44mag between the eyes has worked, but not as quickly and effectively as the slug. I have a deer stand near the pig pen and from the stand experimented with a 30-06 with 165gr partitions and a .270 with 150gr partitions. Aiming immediately behind the ear has usually severed the spine, ending things quickly. With the .410 you need to be fairly close, so for a hunting situation it isn't practical.