- FGC9K -

About

The FGC-9 and the follow-up FGC-9 MKII that was the base of my design eliminates the need for factory-made gun parts or reliance on the advanced fabrication skills of the maker. Fasteners and build materials are available from hardware stores. The entire design works without needing any regulated, commercial gun parts. Even the precision machining to transform a piece of tubing into a barrel are completed at home with a simple operation using a small power supply, a bucket of salt water, and 3D printed jigs.

The original MKII design and build instructions can be found on The Gatalog.

Acknowledgments

The geometry of this design was created by hand in OpenSCAD from measurements taken from the STEP design files of the FGC-9 MkII designed by JStark1809, IvanTheTroll, & 3socksandcrocs and release by Deterrence Dispensed

Status

Incrementally developed over the past few years, my OpenSCAD design is currently finished pending testing. Code will be released, unlicensed, when it is ready.

Build Guide

To complete this gun follow the instructions and documentation of the FGC-9 MKII that this design is based on.

Media

Bonus

The final stage in developing this project was adding the ECM tools. I had put this off because creating the progressive twist in OpenSCAD was a bit daunting to me. I tried a few things, like iterating primitives with rotate() and hull(), but couldn't really do better than a poor approximation that was really slow and just felt clunky. 

I knew the right way to do it was with a bunch of math that built a polygon() point by point. After messing with it for a bit I realized I needed a quick refresh on the semester of calculus I had taken decades ago, but it came together. I needed a parametric model so I could make adjustments to match the design I was attempting to duplicate. So, I was left with script that would be useful to make a custom progressive twist by changing a few variable.

I documented my attempt and you can find that and the script below. It is unlicensed;  feel free to use it in your barrel making experiments and designs. I would be interested in helping to integrate this if someone was interested in creating a parametric set of fixtures.