Not really sure what might constitute a “Mouse” gun but for me anyway, I put the very small, 22 and 25 caliber handguns in this category. Some of these, like the Baby Browning and the Colt Vest Pocket are true firearms icons. Find one of these in mint condition and you better get ready to pay a premium. Then there is the newer stuff like the very well made, but very small, revolvers from Freedom Arms and the inexpensive small derringers from companies like Davis. Back in the 50s and 60s there were some firearms legends that really threw these under the bus as impractical and of little real value to “anyone” and yet this end of the industry seems to have flourished. Some of these just flat scare the begeebers out of me. A family member once gifted me a Freedom Arms revolver in 22LR with all of a 1” barrel. I have large hands and very quickly determined that I could very easily shoot myself in trying to fire that revolver. Had another friend that was fond of carrying a derringer in his front pocket until he hit the door frame of his truck with the hammer of that derringer and it fired in his pocket. Would like to hear from those that carry these types of handguns and why you defer to these as opposed to some of the larger pocket handguns in heavier calibers.