If you are planning on loading it I would highly recommend the 6.5 Grendel. Its ballistics are great even at long distance and it is a great round for prairie dogs, coyotes, Bobcat, Pigs with 95 gr. Hornady V-Maz. And has been good for me for Deer in the 120 gr. bullet range. But as accurate as it gets. With the 95 Gr vs it will turn a prairie dog inside out at 400 yards.
Of course if you want bigger and only need a good 200 yard gun the 458 SOCOM is a monster. It will shoot longer distances but not as flat as the others being 45 Cal. at longer ranges. I shoot a 325 gr. Hornady round in mine for hunting.
One of the other more common calibers that you can buy at a sporting goods retailer without too much trouble is the 6.8 SPC.
The Constitution is not an instrument for the Government to restrain the people. It is an instrument for the people to restrain the Government!
“Americans have the right and advantage of being armed. Unlike the people of other countries, whose leaders are afraid to trust them with arms.”
James Madison. Author of the 2nd Amendment