IS there such a choice? You're going to need one of them "Venn diagrams thingies
" to figure this one out...
Especially for the non-hand-loader, which restricts the shooter to factory ammunition, and ask any experienced hand-loader and you will find that the spectrum for what a cartridge may actually be
depended upon to harvest widens a lot when you hand-load.
So...., If you mean to be technical, the choice for one and only one bore size to "hunt it all" from quail to moose is 12 gauge.
But the OP is asking about a rifle cartridge, so let's stop being "technical" eh? ...,
I first thought of the .243 Win, which is more and more becoming recognized as a well kept secret.
A tad light for stuff larger than a mule deer though, perhaps? OK perhaps good for Elk, but for Moose? For Grizzly?
Fifty years ago it would be a debate between the .30-06, .308 Win, and the .270 Win (maybe throw in a .25-06 advocate too)..., but for bobcat, fox, coyote, a little hard on the pelts to day the least.....
Today, the 6.5 CM or the .260 Remington drop the bullet weight down, so good on deer, and on pelts, again though Moose, and/or Grizzly? (Again leave handloading out of it
) What about the vintage 6.5x55mm Swede, grandad of the 6.5 CM and the .260 Rem ??
So how about the 7mm-08 Remington? Factory loads of 120 grains for medium game, 140's for deer, and 165's for elk and moose?
THEN toss in hand-loading and you get as heavy as 175 grains at a respectable speed, and as light as 100 grains.
And you get pretty much the same depth of bullet selection with a wider range of options, and even up to heavier slugs.... with the .308 Win....
Actually I think you need to have at least two rifles of different calibers...
LD