IMO the 243/6mm is the Hammer of Thor on deer sized game. I have been shooting deer with it since I was 12 and it is still my goto gun for deer and antelope. I had a 6mmRem when I lived in Alaska (still have it) and shot several caribou with it up to 350ish yards with fabulous results. A load that I stumbled on for it was a stout load of 4350 behind a Speer 105gr spitzer; I used that for a long time. Since then I found a load of Rel-19 behind a 85gr Rem cor-lok is too accurate in my gun to ignore. Between the two loads me and my kids have shot 3 caribou, 4 antelope, dozens of deer, two elk...gophers...fox...coyote...some out to the 400 yard area. Not meant to flame but I think the 234/6mm is a little small for elk (I won't do it again). Before that, my folks used 243's for deer hunting in Utah and Oregon and shot a few deer waaaay out there, including some BIG bucks.
Of the standard calibers, I think the 243/6mmRem is about perfect for deer sized animals and under. In about two weeks I should have some photos of my daughter and an antelope for proof; if everything goes as planned.
Genises 27-3: Now therefore take, I pray thee, thy weapons, thy quiver and thy bow, and go out to the field, and take me some venison...