From what I have seen of the deer around central Texas, .223 is big enough for most of them.
The deer up here in Alaska are called moose, best thing against them is a 12 gauge slug. Even up against packs of wolves I would either use some high performance Barnes .223 Triple shocks or just move up a few calibers. After seeing that movie “The Grey” I swore to always carry more than I need in ammo when I head outside. Good excuse to have hi cap mags.