This is a remix of the retention and adjustment screw for the nerf 3D printed blaster called the Multi-Tool. Files can be purchased on Etsy at Multi-Tool. This was done to allow for use of some longer springs so they rest inside the screw and have less pretention on them. They work for both bolt action and pump action configurations. The files and overall design are not mine.
They were done and tested using extra springs for a Firefly and a Caliburn V4. The caps needed to combine with the screw head are avablible with the rest of the files on Etsy.
The author hasn't provided the model origin yet.