The documentation packaged with the MkII refined the electrochemical machining process. The updated jigs made it simpler for novices to achieve consistent rifling depth and accurate headspacing using basic automotive and household electronics. Anatomy of the "Fgc-9-mkii-rev5.zip" Archive
To transform the data inside Fgc-9-mkii-rev5.zip into a functional tool, a maker needs a modest workshop setup:
A complete bill of materials for non-regulated components (screws, springs, metal stock). The Role of Decentralized Design Fgc-9-mkii-rev5.zip
Updated geometry for improved print quality.
The Fgc-9-mkii-rev5.zip is far more than a few 3D models. It is a comprehensive, all-in-one guide for manufacturing not just the gun, but also its ammunition and magazines from scratch. The 2021 MkII release package included: The documentation packaged with the MkII refined the
: Depending on the project, there might be software tools, configuration files, or scripts included to support the project.
The FGC-9 is a pistol-caliber carbine that is notoriously designed to be built without using any regulated firearm parts, making it accessible in jurisdictions with strict gun control laws. The MkII Rev5 includes: The Role of Decentralized Design Updated geometry for
In the US, the legal situation varies by state. At the federal level, the National Firearms Act (NFA) imposes restrictions on barrel length and serialization requirements. In April 2023, a Fort Bragg soldier pleaded guilty to possessing an unregistered short‑barrel rifle after ATF analysis confirmed his FGC‑9 had a barrel less than 16 inches and lacked a serial number. The Biden administration has sought to regulate homemade firearm components more strictly, but the Supreme Court has agreed to consider the constitutionality of those regulations.
Every component, including the magazine and the bolt (which is made from metal stock and a printed housing), can be fabricated at home without purchasing "firearm" parts.
Feeding ramps and ejector geometry were reworked in the MkII to improve compatibility with DIY printed Glock-style magazines. This modification minimized failure-to-feed (FTF) and failure-to-eject (FTE) malfunctions. 4. Streamlined ECM Barrel Process
– A 26‑year‑old gunmaker in Illinois who helped design the ECM barrel‑making process, the Menendez magazines, and much of the additional content in the Rev5 package. He has described the gun’s use as “a tool of liberation” .