Your analogy of squirrel hunting to deer hunting is terribly faulty and you have drawn improper conclusions. I have hunted both deer and squirrels for more than four decades. On squirrels I ONLY take head shots, on deer I NEVER take head shots. Squirrels hit poorly or well but not incapacitated can get themselves into an unrecoverable position before expiring. In addition squirrels have a fragile skeletal structure and the ratio of lead bullet to body mass is significantly higher in the ".22 LR vs squirrel" as opposed to the "180-200 grain vs deer." A fatally wounded deer shot through the lungs (a 10" target) cannot (generally) get to an unrecoverable position and will leave a substantial blood trail. Where as the "attempted" headshot on deer is fraught with opportunities to fail... having outfitted and guided for many years, I have seen more than my share of attempted headshots, and have tracked and not recovered WAY too many of them, bullets through jaws, neck tissue, glancing blows off skulls etc... also, watch deer and watch the quick movements they make with their heads, your actual lethal target is 2 1/2," outside of which you are likely to badly injure but NOT recover the animal... it is true that on a really bad shot you may miss entirely (best case scenario), but considering you are attempting to hit the smallest target to create a fatal outcome, a really bad miss is a ten fold failure, and a slightly bad miss is a disaster.
Headshots on big game animals are just too risky and to my thinking and in my practice should not be promoted.
