Ghost Gun Glossary

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3D Gun Builder

A comprehensive online resource (3dgunbuilder.com) for 3D printed firearms, providing files, guides, and information on building ghost guns at home.

3D Suppressed Sten (3DSS)

A 3D printable firearm design featured on 3dgunbuilder.com, based on the historical Sten submachine gun but modified for civilian legal use.

80 Percent Arms

A leading manufacturer and retailer of 80% lower receivers and frames, known for their GST-9 modular pistol frame system and Easy Jig products.

80% Receiver

An unfinished firearm frame or receiver that requires additional machining to function as a firearm. Typically lacks a serial number and can be bought without a background check.

922(r)

U.S. law restricting the number of imported parts in certain semi-automatic rifles or shotguns. A domestic build cannot have more than 10 imported parts from a specific list.

A

ABS

A strong, heat-resistant filament used in 3D printing. Suitable for durable gun parts but prone to warping.

Additive Manufacturing

The process of creating objects by adding material layer by layer, commonly used in 3D printing of firearm components.

AR-15

A popular modular semi-automatic rifle platform. The lower receiver is the serialized, regulated part.

ATF

The Bureau of Alcohol, Tobacco, Firearms, and Explosives, a U.S. federal agency regulating firearms.

AWCY?

"Are We Cool Yet?" - An online collective creating and sharing open-source 3D-printed firearm designs.

Auto Sear

A device used to convert a semi-automatic firearm to fully automatic. Highly regulated as a machinegun part.

B

Barrel

The tube through which a projectile is fired. Usually metal, and a critical part of firearm accuracy and safety.

Black Lotus Coalition

A group of 3D gun designers who create and share firearm files and improvements, with designs featured on sites like 3dgunbuilder.com.

Blazing Fast Shipping

A marketing term used by retailers like Husky Armory to emphasize quick delivery of ghost gun components directly to customers' doors.

Blowback

A simple semi-automatic firearm action using pressure from fired cartridges to cycle the action.

Buffer Tube

A tube on AR-style rifles that houses the recoil spring and provides a mounting point for a stock.

Build Kit

A collection of parts, often sold together, that allows an individual to assemble a firearm. These kits typically include an 80% receiver or frame and components like barrels, triggers, and grips, commonly used to create unserialized ghost guns.

C

CAD

Computer-Aided Design software used to create digital models for 3D printing and CNC machining.

CNC

Computer Numerical Control, a method of automated machining used to finish 80% lowers and frames.

Conversion Device

Any part that turns a semi-automatic firearm into a fully automatic one. Treated as a machinegun under U.S. law.

CtrlPew

An online platform that hosts open-source designs for 3D-printed firearms and firearm parts. It supports the DIY firearm community by providing freely accessible files for personal manufacturing.

Cura Ultimaker

A popular free slicing software used to prepare 3D gun models for printing, offering specific settings profiles optimized for firearm components.

D

DD19.2

A popular 3D printable Glock 19 compatible frame design, featuring enhanced ergonomics and compatibility with standard Glock components.

Decimator 22

A 3D printable .22 caliber firearm design created by the developer "Decimal" and distributed through DIY gun file sharing platforms.

DefCad

A controversial online repository and distribution platform for 3D printable firearm files and designs, founded by Cody Wilson. The site has been at the center of legal battles regarding the First and Second Amendments, digital rights, and firearm regulations.

Deterrence Dispensed

An online collective releasing open-source firearm designs, known for the FGC-9 and other projects.

DIY Firearm

A homemade gun crafted from raw materials, unfinished parts, or 3D-printed components.

Drilling

A machining process used to create precise holes in materials, often a critical step in finishing an 80% receiver or frame. It is typically performed with a jig to ensure accuracy and functionality.

E

eSUN

A popular brand of 3D printing filament widely used in the DIY firearm community, particularly known for their PLA+ which is often recommended for printing gun frames and components.

F

FCU

Fire Control Unit, the serialized core of modular pistols like the SIG P320.

FDM

Fused Deposition Modeling, a popular 3D printing technique using filament to build parts layer by layer.

FGC-9

A 3D-printed semi-automatic carbine designed to be made without regulated parts. The name stands for "Fuck Gun Control 9mm," a pistol caliber carbine designed by JStark to be built with minimal regulated parts.

Firearm Precursor Part

A legal term used in some states like California to describe 80% frames and receivers, subjecting them to additional regulations or prohibitions.

Flared Magwell

An enlarged magazine well opening on premium 80% frames that facilitates faster and more reliable magazine changes during reloads.

Frame and Receiver Rule

A 2022 ATF regulation requiring unfinished frames and receivers, such as 80% lowers, to be serialized and sold with background checks. This rule, aimed at curbing ghost guns, was upheld by the U.S. Supreme Court in 2025.

Frame Rails

Metal inserts that provide a wear surface for the slide to travel on in polymer 80% frames, typically made of stainless steel and often sold separately from the frame due to regulations.

G

Gas Pedal

A contoured area on some 80% frames like the GST-9 MOD1 that provides a resting place for the support hand thumb, designed to help control recoil and improve shooting accuracy.

Geisler Defence 19x

A premium 80% frame dubbed the "Polymer 80 Killer," combining a Glock 17-style grip with Glock 19 slide compatibility, known for enhanced ergonomics and superior grip texture. Available from Husky Armory.

Ghost Gun

A privately made firearm lacking a serial number, often constructed from unfinished parts or 3D-printed components.

Glock Frame

The lower part of a Glock pistol, typically polymer, that houses the trigger assembly.

Glock Switch

A small device that attaches to the rear of a Glock pistol slide, converting it from semi-automatic to fully automatic operation. These devices, which can be 3D printed, are classified as machine gun conversion devices by the ATF and are illegal for civilian possession without proper licensing.

GST-9

A modular 80% pistol frame system produced by 80 Percent Arms, compatible with Glock 19 Gen 3 components and offering a 4-in-1 platform that can be configured in multiple sizes.

Gun Control Act (GCA)

A U.S. federal law enacted in 1968 that regulates the firearms industry and owners. It defines what constitutes a firearm and mandates serialization and background checks for commercial sales.

GunCAD Index

A searchable catalog of 3D printable firearm designs, components, and accessories, serving as a reference library for the DIY gun community.

H

Harlot 22LR

A simple, fully 3D printable single-shot .22LR pistol design available through 3D gun file repositories, intended as an entry-level project for beginners.

Homemade Firearm

Any firearm made by an individual for personal use rather than by a licensed manufacturer.

Husky Armory

An online retailer specializing in 80% frames, build kits, and parts for DIY firearms, offering products from brands like Geisler Defence and Polymer 80.

Hybrid Design

A feature of some 80% frames like the Geisler Defence 19x that combines elements from different firearm models, such as a full-size grip with a compact slide.

I

Iditarod Slide Kit

A complete slide assembly compatible with Glock-pattern 80% frames, including barrel, recoil spring, and internal components. Available from Husky Armory.

ImmortalRevolt

A 3D gun designer known for creating innovative firearm designs shared through platforms like 3dgunbuilder.com and other file repositories.

Infill Percentage

The amount of material used inside a 3D printed gun part, expressed as a percentage, with higher percentages (80-100%) recommended for critical firearm components to ensure structural integrity.

Ivan the Troll

A prominent figure in the 3D printed firearms community known for designing and distributing various 3D printable gun files and components. He has been instrumental in advancing DIY firearm technology and has collaborated on projects like the FGC-9, becoming a controversial figure in debates over gun control and digital rights.

J

Jig

A tool used to guide drilling and milling when finishing an 80% receiver or frame. It's a plastic or metal template that ensures proper placement of holes and cuts.

JStark

The pseudonym of Jacob Duygu, a German-Kurdish gun designer who created the FGC-9 (Fuck Gun Control 9mm), a semiautomatic 9mm carbine designed to be built with minimal regulated parts. JStark became an iconic figure in the 3D printed gun community before his untimely death in 2021.

L

Layer Height

The thickness of each printed layer in a 3D printed firearm component, typically measured in millimeters (0.1-0.2mm), with smaller heights producing smoother but slower prints.

Locking Block

A critical component included with 80% frame kits that reinforces the frame and provides a surface for the slide to lock against during cycling.

M

Milling

A machining process that removes material to create firearm parts, often done with CNC machines.

Modular Frame System

A ghost gun design feature allowing a single frame to be configured in multiple ways, such as the GST-9's ability to function as four different pistol sizes.

N

Nylon

A durable 3D printing filament used for high-strength gun parts, such as frames and grips.

P

Parts Kit

A collection of components needed to complete a ghost gun build, excluding the regulated receiver or frame which must be obtained separately or manufactured at home.

PLA

A biodegradable thermoplastic filament used in 3D printing, known for its affordability and ease of use. It is less durable than materials like ABS or nylon, making it less ideal for high-stress firearm components.

PLA+

An enhanced version of standard PLA filament with improved strength and impact resistance, commonly recommended for 3D printed firearm frames and components due to its balance of printability and durability.

Plastikov

A 3D printable AK-47 pattern rifle that uses commercially available parts kits combined with printed receiver components, popularized through platforms like 3dgunbuilder.com.

Polymer 80 PF940C

A popular 80% frame for Glock 19-sized pistols, featuring an aggressive grip texture and requiring completion with a jig and tools.

Polymer80

A company known for producing 80% frames and receivers, especially for Glock-style handguns. Their products are popular in ghost gun construction due to their ease of completion without serialization.

Post Processing

The finishing work done after 3D printing gun parts, including removing support material, sanding surfaces, and heat treating components to improve strength and durability.

Print Orientation

The positioning of a 3D model on the print bed, critical for firearm components as it affects strength along stress lines and dimensional accuracy of critical features.

Printerviews

A section on 3dgunbuilder.com featuring interviews with prominent designers and contributors in the 3D printed firearms community.

Privately Made Firearm (PMF)

A term used by the ATF to describe firearms crafted by non-licensees, often lacking serial numbers. PMFs are typically made using 80% frames, 3D printing, or other DIY methods and are subject to regulatory scrutiny.

R

Rails Down

A common 3D printing orientation where the frame is printed with the rail slots facing downward toward the print bed, often recommended for beginners due to better dimensional accuracy and strength.

Receiver

The serialized part of a firearm that houses critical components like the trigger group or bolt.

Regulatory Information

Legal disclaimers and shipping restrictions that accompany 80% frames due to varying state and federal laws regarding unserialized firearm components.

Resin

A liquid photopolymer used in SLA printing, offering high detail but often brittle when fully cured.

Rogue 9

A 3D printable 9mm firearm design featured on 3dgunbuilder.com, designed for maximum printability with minimal commercial parts.

S

SLA

Stereolithography, a 3D printing process using resin cured by UV light.

Slicer

Software that converts 3D models (STL files) into G-code instructions for 3D printers, with Cura and PrusaSlicer being popular choices in the DIY gun community.

STL File

A file format used in 3D printing to define the surface geometry of a 3D object. It is widely shared online for firearm parts, enabling individuals to print their own components at home.

Swift Link

A 3D printable auto sear designed for AR-15 platform firearms that enables full-auto fire by manipulating the disconnector. This device is classified as a machine gun part by the ATF and is heavily regulated under federal law, with possession potentially resulting in serious legal penalties.

T

The FOSSCAD Megapack

A collection of open-source firearm designs distributed online, often used for 3D-printed guns and parts. It reflects the growing trend of decentralized, community-driven firearm manufacturing.

Trigger Group

A set of parts that actuate a firearm's firing mechanism when the trigger is pulled.

U

Unserialized

A characteristic of ghost guns and privately made firearms that lack serial numbers, rendering them untraceable by law enforcement. This feature is central to debates over DIY firearm regulation.

V

VanDerStok v. Garland

A court case challenging the ATF's rule on ghost gun kits, ultimately upheld by the Supreme Court.

W

Warping

An undesired deformation in 3D printed gun parts caused by material cooling and shrinking unevenly, potentially compromising the functionality and safety of the component.

Z

Zip Gun

A crude homemade firearm made from improvised materials, often illegal due to safety concerns.