Yes I've had these thoughts, especially when hunting narrow long right of way cuts through thick timber or brush. I think it is just pre hunt anxiety mostly, because when you see an exit wound on a deer, can you tell what caliber it was killed with? I wouldn't want to bet much on getting this right, because I've seen some large exits from a .270 Speer hotcor and some small exits from a 7mm accubond and .300 TSX.
I personally would want to choose a "deer" bullet and try to pay close attention to exact location where critter was at last sighting with any caliber because there may not be any blood on the ground at beginning of death sprint.
