I just whacked a big chuck this a.m. with a Gamo .177 "Bone Collector" series break open air gun. It's far from a fine gun, but works well and the 3x9 scope works well. Got it for less than $300, no tax, free shipping, TYD:

http://www.amazon.com/Gamo-Bone-Collector-air-rifle/dp/B0039OA5MM

The only fault I find with it is a pretty hard trigger, but I've gotten used to it.