See it in action here: https://youtu.be/eyxTQXKrBKg
Wristmounted manual version is here https://www.thingiverse.com/thing:3430263
I designed this to mount on a mini rc tank. Its designed to plug into a receiver for wireless operation.
You could however bypass the esc on the servo and connect the motor directly to a switch and battery.
You'll need a continous rotation 9g servo. I modded a cheap regular 9g servo into full rotation.
Cut one servo arm to size and glue it on the "servo gear" Except for this part, i didnt glue anything.
Everything is correctly orientated and I did not use any supports, except for the servo gear.
I used a hollow Q-tip on the guide rail. I inserted a piece of (1.75mm) filament for strength.
Maybe some light sanding here and there.
You can squeeze the trigger for single shots or hold it to fire all rounds. See end of video for reloading.
It shoots at around 6-8 meters. You can lenghthen the front barrel for more speed and distance.
I attached the servo to a toy car rx combo for testing.
See pictures for assembly. Some components are slightly different on the pictures as i reedited some components.
Edit: Fixed the ring to hold the body and barrel