I'd say that I would agree with rem270 on this one cause of my experience hunting with a juv.
What I experienced was very little or no blood to trail with a broadside shot through the lungs.
Now in the hands of an experienced marksman, a neck shot, head shot, will on the other hand require no tracking. Ha
I have seen many a dead whitetail fall to a neck shot with a similar round, the 22-250!!!.
The correct .223/5.56 is just fine for deer, but has it's limitations like all the smaller caliber rifles. It will do just as much if not more damage to a deer than a broadhead. So unless you are against bow hunting, then you do not have any reason to be against using the .223/5.56.