I have killed a pile of deer with 100g 243 and the only time I had runners were with premium bullets that left 2 holes every time, I shoot 150 corelocks in my 300wm, have had 2 runners that were heart shot, 2 holes on each, 100y couldn't believe it tapped the 2nd deer 1/4 away and hit within a inch of the first shot. I rather leave all the energy dumped into the deer. Elk I would say 180g but not needed for deer size game