RPRNY;
I've hunted Wyoming and Montana big game for decades, currently living in Montana. The pronghorn can be very successfully hunted with either the .30-06 or the 6.5 Swede. I've taken goats with both calibers. The ought-6 has downed a nice pronghorn buck at 470 lazed yards, and I've hit gongs at 675 with the Swede. Learn to hunt the speed goat and you won't need anything other than what you've got. And speaking of what you've got, you need a .270 like you need another hole in the head.
The .444 will do just fine for short-range large animal work, but starts to resemble a mortar more than a rifle when the range is extended. I've got a .338 Winchester magnum, and I'll freely admit that it's a screaming beach to shoot off the bench. But, for one shot on an elk at range, it's what you want to have and you'll never feel the recoil. Use a 225 grain bullet and it'll go through a 4" pine tree and drop the bull on the other side of it at 400 yards. That 225 will, depending on your load, leave the muzzle carrying somewhere around 3500 to 4000 ft. lb's. of energy. Enough to get the job done on bear, moose, or elk, even if they're on the other side of a coulee.
Know the gun, know the cartridge, know what it'll do, and go hunt. But, study the hunting, you'll make it a ton easier on yourself.
900F