Personally, I'd say .243... BUT hordes and legions of Texas hunters swear by the .22-250 and .223. Now, caliber is different than CARTRIDGE.
as said before a .25acp does not equal a .25-'06
a smaller caliber in a large case can be more powerful than a larger caliber such as say a .223 vs a .45acp
NGH
There is a lot of difference in say, a 22.250 and a 22 hornet, both of which are legal for deer in Ga. Would I use a hornet? Not if I could help it, but if I did, I would treat the situation much differently than with the 22.250. Again, I say the caliber is less important than the hunter. Does he really know his cartridge? Will he try a 225yd. shot with a Hornet? Can he place the bullet in the heart or head, or is he just trying for a body shot anywhere as so many do?
I hunted with a guy, ONCE, that used a 12 ga. with slugs. At about 150 yds. he managed out of five shots to get two in a deer. I tracked the deer well off our property, and found it bogged in a swamp with it's intestines floating. I dispatched it with my 22 pocket pistol and left it for the coyotes. Too far to carry, and the shooter had gone home.
I would never have tried the shot with the slugs at that distance, because with a smooth bore slug gun I would doubt my ability to dispatch the animal. I would have with a 22.250.....a 22 Hornet?..nope.
Ben