I have an Encore rifle by Thompson Center. As you guys probably know you can buy about any caliber you might want. Sooooo....I'd like to buy a varmint barrel for groundhogs and maybe coyotes, although I have never hunted coyotes...yet. Which caliber barrel should I buy? 223? 22-250? Some other caliber? I am interested in the varmint calibers because I have been told that the rounds tend to fragment when the hit the critter or the ground and therefore might be better from a safety prospective than a deer type round.