im 17 and havent hunted b4, but the 223 is the m16 round, and would placement of the shot be more than the size of the bullet? a 22lr thru the eye would kill bout any thing would it, i have even heard of russins making a .22cal SNIPER rifle, (the 22 cal for the sniper works at short rang and isnt to loud and wilnt kick up all the dead leaves in a 10foot area, and a well place shot would do it) but my point is, that a 223 put in the right place would kiss a deer, but if u miss, well bad...where as with a larger bullet u might have a better chance of killing it with a shot just a little off, but then again im 17 and not a hunter, so there is a good chance im wrong....i hope i helped and not just sounded stupid