This is a case for The Uhltimate Rubber Band Gun. This gun functions well and I wanted something to store the different sized barrels and targets in. I printed some of these for my Nephews for Christmas. I am not posting pictures of theirs, but I added their names into the lid for each of them for a little customization.

I designed this in TinkerCAD. If you would like to modify it, you can access the original here: https://www.tinkercad.com/things/kKpSedhQgKx-rubberbandguncase