I love my .243 Sako A7 and from my very limited deer experience thus far, am satisfied that it 'does the job'. My first two deer, both neck shot Fallow at ~40 and ~50 metres respectively, both went down on the spot. However, I would suggest only because so close and the shots were placed accurately enough to sever the spinal column quickly and cleanly. The (first) three Roe I shot the other day (all good boiler room shots but at 160m, 170m and 180m respectively) all made 15-20m before going down. So, from my very limited experience (although backed up with the military principle of 7.62mm being designed to put down hard and cause maximum damage vs. 5.56 mm conceding hitting power for lower recoil and a much higher average of 'good' shots as a result, along with the ability to carry significantly higher volumes of rounds), I concede to the simple logic that a larger round hitting harder if placed as accurately, stands a greater likelihood of putting them down on the spot. To this end, I am thinking as you Dagben; I will add a .308 dedicated deer rifle and move the .243 to foxing/spare, knowing I can still use for deer if out for foxes and a deer need/opportunity presents itself.