"lung soup" is what I got. less than 75 yard run and the head lowered to the point a spike caught and a somersault resulted. No movement followed. It wasn't a bad kill.
I previously shot one in the neck and hit the spine there(it was running behind a log when I shot so I could only see the neck). That took a bit longer for the death although it stopped where it was. Another time I was walking back to camp with two buddies and one jumped up with-in 10 yards. It died from multiple hits. I have seen some others taken from a variety of shots. The only really bad one was a running deer on a drive where the back hip was what was hit. Stopped the deer where it was, but took another shot to kill it and it ruined a lot of meat.
With my shotgun a headshot would be out of the question at any range. With a pistol also. Maybe off a rest with great irons or a scope at pretty close range. My muzzle loader is a Thompson Center that is very accurate with really nice stock irons and at the range I was at I would feel very comfortable with a headshot. I was very glad I had sighted my irons and set-up with see through rings. Would have been far more difficult shooting with the scope.