My sargent shot a deer one time. One of those small Asian deer. Hit it square in the chest from about 40 yds. M-16 .223. Wham. I saw the hit.
Damn thing could not have weighed 60 pounds. Down. Wrong.
Deer stood up. Looked at us and said "That all you got." WTF. Holy S#@$T.
And I'm supposed to shoot people with this.

We never did find the deer. It headed for the hills.
Word I got from the Somalia vets is the Somalia troops were whacked out on some kind of stimulant that a .44 mag could not stop them.
Is the .223 working?? Best let the younger vets tell us I guess. Maybe they have a better bullet now. I don't know.