I had a lot of fun with the original rubber band gun. But I thought about some improvements, like a working safety, a slide release or an ejectable magazine. And with heavy loads, the slide deformed upwards and the rotor did not stop (the idea of the SIDE_GUIDE was born). The safety and slide release were easy to implement - I made the SIDE_PLATE_LEFT and SIDE_PLATE_RIGHT 2 millimeters thinner. To print the slide without support, I implemented a hexagonal barrel and a new round muzzle. Trigger variations can now be easily changed without reprinting the entire slide. The biggest and a huge change was the implementation of the new magazine. Rubber bands can be stored there. As a result, the only compatible things to the original are the GRIP_LEFT and GRIP_RIGHT!

UPDATE 09/10/2022:
I see some of you are having problems with 3D printing. Still maybe useful tips: Ender 3 v2 printer, Black PLA filament (this was the only one I had at the time), maximum speed 50 mm/s, layer height 0.12 - 0.16, the individual parts must be aligned in CURA. Both PINs with 100% filling. All parts I printed with a 3 layer raft! The gap of the MAG_RELEASE buttons in the SIDE_PLATEs is designed very, very small and must be sanded with sandpaper to fit, so very little wobbles. My printing time was at least a week, in the evening or overnight. And this Thing is not for beginners, you must have some experience with other Things and the features of your printer. I'm thinking about printing another gun when I have brighter filament and making a video for you of the assembly...

UPDATE 11/20/2022:
Added new first image. Aligned all stl files to print, added descriptions for support and selectable different design options. No changes to the meshes!

Original:
https://www.thingiverse.com/thing:3053501

Trigger with holes:
(idea from, but remeshed)
https://www.thingiverse.com/thing:4897932

Grip Punisher, Slide with Text (NOWY_ZAMEK.stl):
(Slide: only text taken, new positioned)
(Punisher: logo taken and cutted in default grip)
https://www.thingiverse.com/thing:3789874

Grip Hitman:
(unchanged)
https://www.thingiverse.com/thing:3851104