I like to shoot a Ruger 220 swift and a Remington 700 in .243 for most of my predator hunting. I usually shoot the .243 if the wind is blowing a little stiffer. My old man shoots a .204 and 22-250. I would say that anything between a .204 and 25-06 would be a good caliber choice for predators, and maybe some of the .17 caliber rifles if you are cloase and there isn't much wind where you are. It just depends on what you want, whether you reload or not (I wouldn't recommend the 220 swift to anyone that doesn't reload because ammo is fricken expensive), and how far you are going to shoot regularly. Remember that the bigger the caliber the larger the whole it will make as well. A lot of times I shoot a match bullet out of my .243 because it punches a pin hole through the dog whereas a V-Max or ballistic tip will often times blow up on the shoulder and leave a huge whole reducing the amount of money you will get for the pelt. Like I said, it just depends on what you are doing and what you want out of it. My $.02 on the matter. Don't know if that helps or makes it worse