Two good ideas
Motivated by my new Gun Disassembly toy I found a few interesting websites with interesting articles that made me realize that I don't really need to cut of my cartridge designs, just modify them a bit if I can. And almost all ideas I have consist of multiple cartridges and internal magazines - which's a good thing cause I almost started to throw this dream away. Inspired by the very interesting Mars Pistol I came up with an interesting idea of cycling a cartridge-based Lego gun. The cartridges are stored in an internal spring-powered magazine under the barrel. The top-most cartridge and the currently chambered cartridge reside in a rotatable revolver-like cylinder that can be pulled back and rotated, ejecting the chambered cartridge as well as moving the top-most cartridge into the chamber. The problem I see is how the cartridges are supposed to stick to the cylinder if you need both sides open for rechambering from the top side. Well, I guess I'll to find some clever use of bendable Lego parts for that. In chambered state, however, there's no rotation, just fixation. The complete operation does thus operates a bit like a bolt-action but with continuous rotation. Empty cartridges could theoretically even be dumped into a bag below... very interesting all that. The second interesting realisation I had was about derringer designs. They seem to just use an alternating striker position to trigger which barrel will be fired with a ratchet featuring alternating teeth height. Similar to how revolver rotate barrel with a ratchet, this approach just "rotates" the selected barrel. Using seperation of the rotating element and the ramming part, this should work I think. Hm, thinking of some more compactness, this could make a pistol-like gun with no cartridges at all... I'm even thinking about tri-barrel arangements if the rotating part gues well. Well, I'm totally into this thinking right now. Need to begin some drafts tomorrow evening, this could be fun... Oh and I don't even dare to think about starting construction cause I know I'll be depressed if Lego's ones again limiting my plans. Thus, I'm just doing a bit of daydreaming with schematics and drawings.