From the classic anime Outlaw Star, this is my take on Gene Starwind's Caster gun. Be warned, the grip isn't the most comfortable, and the rear sight doesn't rotate easily without some extra finishing work.
The parts are mostly split for ease of printing and painting, then should only take a few dabs of glue to hold everything together. For my copy, I used the spring from a pen to give the breech shell loader some give, but that's optional.
Print 2 each of the breech lock cylinder, front trigger cylinder, and glue them each together in the middle. Everything else is 1 print each. Depending on how you orient things, most parts shouldn't need support material, though the shell loader will if you print one, and the breech lock arm and spinners will as well.
This is printed mostly hollow so you can add lights if desired. A battery pack can fit in the breech / main body section, and wires can be run down the length of the body. I set up my spinner rings and emitter using diffusion plastic and 12V LED light strips, powered by a 9V battery in the breech area. If you go rechargeable, you should be able to fit those in the grip itself and install a recharge port somewhere convenient.
