Exotic calibers are cool, but...
"George Gardner of GA Precision recently won the long-range Shumway Cup segment of the 2006 Snipers' Hide Cup shooting a straight .243 Win. In so doing, George bested Terry Cross (.260 Rem) and David Tubb (6XC), so you can see the .243 is a top performer at long distances. In fact, in terms of Wind Drift, a .243 running 115s at 3150 fps beats both the .260 Rem (2850 fps) and the 6.5-284 (2950 fps) running 142 MatchKings."
If I was going to try to shoot against the big boys, I would go with a bench rest favorite. If I wanted a rifle with broader function, I would probably stick with something that's more common, and just tweak it up. With all other things equal (rifle, bullets, optics, and shooter), it won't make much difference, especially on a deer.