Silly shell holder for the Nessie blaster: https://www.printables.com/model/1409567-nessie-lowoptional-hardware-silly-shell-blaster
Holds 4 silly shells on the side of the blaster for easy access and reloading, you can print one for the left, right or both sides if you're feeling adventurous. I have printed one for the left side as I am right handed.
It is designed to sit perfectly on the side of the blaster, it is obvious where it attaches once printed.
I stuck it in place using 5 minute epoxy, but important to note that I stuck it ONLY ON THE FRONT SECTION (below in blue, ‘FRAME B’):


I spread the epoxy on the cylindrical section, with the circular indents.
By gluing it to one section, the blaster can still be disassembled. The sections should slide apart despite the rear two shell holder clips still sitting flush against ‘frame C’, in yellow.
The author remixed this model.
It uses the same clips that hold the shells from the original model, but modified to fit on the side of the Nessie: https://www.printables.com/model/1409567-nessie-lowoptional-hardware-silly-shell-blaster