RE: 22 derringer
I agree with RR, the Davis(Cobra) is junk!! Along with the ones from Bond and High Standard, another company making quality derringers is the American Derringer Co, but I don't know if they offer them in 22cal. If you're not set on a derringer, check out the mini revolvers from North American Arms or look for a used mini from Freedom Arms. They're actually smaller than a derringer and you've got 3 more rounds.