[AnTiw1]

I knew a gunsmith in Wyoming who would cruise pawn shops looking for over and unders, which he would transform into huge 12 gauge derringers.

Illegal as hell, apparently. He still had a lot of customers, and he wasn't cheap...first class hand cannons, look just like the grandpappy of all derringers.

[Ronin]

That’s what I’m talking about!

Probably break your wrist to fire the thing, but hey, plaster casts are cheaper than coffins.