Why would you carry two rounds when you can carry five or six or seven in a package of similar weight? I'm not a fan of derringers for anything but attracting interest at the range ... got rid of my 9mm (admittedly, it didn't weigh 15oz) when I realized it was pretty much useless for self-defense ... Mine was nothing but a range toy, fun to shoot but incredibly inaccurate, hard to cock, slow to reload ...