My little cousin snuck up on one, literally crawled on his belly through knee high grass, and got one with a BB-gun. I won't give you the details, but I did see it, and it was funny as hell, sort of. That little kid was never happier!
I used to use a .22. Got a bunch of them that way. I use a .270 to keep in practice for deer season. The .44 is fun, cleanup is messy, somewhat unnecessary if you get them before a good rain. And the .50 cal flint lock, well...I've carried it a few times, shot a few times at the little bastards with it, but I don't know if I hit anything or not. By the time the smoke clears, I'm not even sure what general area I was aiming for.