I doubt that the cartridge is the problem, the .30/06 answers most questions in good workman like fashion, but a long barreled rifle with a large optic that I envision being chosen for long range big game hunting is not one that would necessarily prove particularly handy for shooting a grizzly in the willows at "blood on the shoes" range. However, neither is an iron sighted carbine with a short stock, ideal for a 500 yard shot on a sheep.
Of course I've already answered the question with my 20" .375 Ultra. Loaded with a 260 gr AB or a 250 gr TTSX at 2900 fps from the short pipe, it'll reach out there like a 7mm magnum, and still be handy enough to tackle a bear in the thick stuff. If the bear issue is not on your radar, then just get a good .270 and go hunting. But for all the naysayers, I'm frankly more likely to have an up close bear problem then I am to take a 500 yard shot on a sheep.