http://www.sportsmansguide.com/cb/cb.asp?a=58422

I've had 2 of these guns. The first one died after about 2 years (found out you're not supposed to leave the CO2 cartridge in when not in use.) It's sweet. 12 round magazine, semi-automatic. You can squeeze off all 12 shots in about 2-3 seconds. I've mounted both a 4X optical scope and a laser scope on it. 625 fps- faster than almost any pellet handgun, and more accurate as well.

I have a larger, pneumatic break-barrel airgun that is 1100 fps and super-accurate, but it's at my parents and I can't remember what brand it is. But I've used it (with scope) to pick off prairie dogs at 200 feet. That thing has more kick than some of the .22's I've fired.

I use both of these guns to hunt rabbits, prairie dogs, and crows at my parents place. The break-barrel is nice because you don't have to keep a supply of CO2 and each shot counts more, but the single-shot capacity means you had better make that first shot count. The semi-auto is great for walking through the brush and taking multiple shots, but it's range and power is limited.

Edit-- and I've never had a pellet jam and come back at me with either of these guns.