its really not all that hard to imagine a handgun where the hammer drops to the bottom cilinder rather than the top cilinder. i dont know why youd make a gun like that (probably something to do with the plot) but to say its nonsensicle is a bit of a stretch.
The Chiappa Rhino is another model that fires from the bottom cylinder. The reason it's not more common is that the mechanism tends to be considerably more complex. A revolver isn't as simple as it seems from the outside.
A revolver concept is another maybe with the images I see above images above, though of course it is one thing for something to work in concept & another in action.
hmm... you'd sacrifice much of what is normally magazine capacity , you're not getting more than a few rounds in there, so a revolver isn't an awful idea
Idea #1: gyrojet with electrical primer. These could more or less be fired straight out of a magazine and into a very short barrel. All you'd have to squeeze into the grip still is battery and it could fire as quickly as the capacitor can charge
Idea #2: with conventional cartridges, you can use a setup similar to the Dardick handgun above but without "Trounds". Simply make make it belt-fed, just a short belt. And just go from there, regular revolver with no/minimal barrel
