This is a simplified model of a Jawa ion blaster as seen in various Star Wars media. It's not 100% true to any particular style, but is heavily based on the version in A New Hope.
I made this for my 5 year old daughter, so I printed it at 75% for her. The exception to the scale down is the panel for holding the LEDs. Since the holes had to remain 5mm, I made two versions of that: led_panel_100 and led_panel_75. Just print the one you need for your scale.
The connector pin for the stock and body needs to be printed twice.
It is designed to have the barrel held into place with screws. Use 4mm screws for 100% scale and 3mm screws for 75%.
For lights, I used 8 3V blue LEDs wired to a 3V coin style battery, with a trigger switch. I'll post up details of the wiring once I actually finish mine.
You can find pics of my progress on my instagram page: https://www.instagram.com/stormtrooperguy/