Adding my 2cents....I would go with a .204 ruger for a varmint caliber. Why? It's a neat cartridge! I had a 22-250 barrel for my encore and traded it. Not that it is a bad cartridge by any means, but I would have prefered to be able to spot hits through my scope. That would be very useful at long range, not only to see the effects on your target but also in the event you missed. You could see where the bullet landed and adjust accordingly. Plus, if you reload it uses less powder as someone else said.
Also, while we are talking barrels....I have a .17hmr barrel for my encore and it's big time fun. If you're just going after gophers and whatnot out to 150-200 yards why not check out this caliber? The other day at the range I picked some walnuts from a tree that grows near the rifle range and set them in the dirt of the backstop at 100 yards. I had great fun exploding walnuts at that range with that little cartridge. Compared to centerfire, the rounds are fairly inexpensive...about 13 bucks a box or so. Worth looking into.
