The FMGCZ-01 refers to a design within the 3D-printed community for a compact, automatic arm based on the architecture of the FGC-9. Unlike traditional AR-15 platforms that utilize a buffer tube assembly extending from the rear of the receiver, this specific design modifies the layout to operate without a standard buffer tube to reduce the overall profile. Discussion and documentation regarding these designs typically exist within dedicated to downloadable link
stl 9 mm sized file
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The FMGCZ-01 completely overhauls the standard FGC-9 layout to function as a compact machine pistol or ultra-short personal defense weapon: [1, 2]
- Bufferless Architecture: Traditional FGC-9 and AR-15 designs require a prominent buffer tube extending from the rear of the lower receiver to host the recoil system. The FMGCZ-01 completely eliminates the buffer tube, integrating the recoil mechanism entirely inside the upper receiver. This allows the firearm to be outfitted with a collapsible, retractable stock or a completely flat rear cap.
Select-Fire Capabilities: The core differentiation of this variant is a modified internal geometry that converts the standard semi-automatic AR-15/FGC-9 fire control group into a selective-fire or fully automatic system. It adopts modified components resembling an M16/automatic fire control group layout, including a integrated sear trip.
Modified Bolt and Ejector: The design features a modified, slightly lightened blowback bolt that shifts mass to the front. It replaces the traditional printed ejector block with a custom, high-durability ejector fashioned out of a common 3mm steel rod.
- Magazine Compatibility: Unlike the original FGC-9, which natively feeds from Glock-style or proprietary Menendez printed magazines, the FMGC-01 is commonly built to adapt Sten-style straight magazines to preserve a retro, boxy aesthetic while enhancing capacity up to 30 rounds.
- DIY Assembly Optimizations: The design relies heavily on threaded heat-set metal inserts rather than plastic-on-plastic threading, reducing wear over multiple maintenance cycles. The front pin connecting the upper and lower receivers acts as a structural pivot point for rapid field stripping.
- FMGCZ-01 remains a “100% DIY” project.
