I see what your saying, and I agree. You wouldn't take a .223 white tail hunting with conventional loads, but a .242 does the job. If you really look at it though from within a 100yds and with similar loads the difference is neglegable. Are .243 going to do more damage generally ? I'd say yes but can you load / buy .223 ammo that would do the same? Sure thing!

But you are absolutely right with the .223 being a smaller "varmit" round it's designed to shoot flatter and faster.

In my mind if you are not a youngin, or small framed and you are hunting with a .223 you are doing so for the flatness or the round and would be more likely to aim for vitals. That being said, if you don't make a good shot on a whitetail with a .243 you are going to have a he'll of a time recovering the animal.

I guess most simply though. What I meant was with an animal of that size and from that range the difference in the rounds would not be great. Again if they are hand loaded rounds everything kinda goes out the window. The .243 though, being heavuer, would have more stopping power whereas the .223 would probably go through and through or stop in hard muscle.