This is an airsoft grenade launcher, it holds airsoft grenades size 40 mm diameter. The pictures show what needs to go where, you can also study the gun itself from the pictures. You can pick your screws, just as long as they are not to big in diameter, or else the side parts will split. But you can also use glue.

WARNING; This requires a lot of tweaking to be able to work properly. you have been warned.

I have listed below the grenade I bought for this project.

Matrix Eagle Force High Power Multi-Purpose CNC 40mm Airsoft Grenade Shell (Qty: One), Accessories & Parts, Launcher Shells & Projectiles - Evike.com Airsoft Superstore

The information, like print time, and filament use are in the pictures section.