There is a significant amount of misinformation surrounding the term “ghost gun.” Much of this stems from pop culture myths—popularized by 1980s films like Die Hard—suggesting these weapons are invisible to airport X-ray machines.
This is false. Because these firearms rely on critical metal components to function (such as the barrel, slide, and firing mechanism), they are easily detected by standard security scanners. The term “ghost” does not refer to physical invisibility, but rather to legal invisibility.
What is a Ghost Gun?
A “ghost gun” is a firearm that lacks a serial number and is effectively invisible to government databases. They are “ghosts” because they cannot be traced, not because they cannot be seen.
This concept exploits a specific nuance in United States law. In the U.S., the federal government regulates the sale of firearms, but individuals have historically been allowed to manufacture their own firearms for personal use (provided they do not intend to sell them).
How Are They Made? (The “80%” Loophole)
To understand ghost guns, one must understand the “receiver” or “frame.” In the eyes of the law, the frame is the only part of the weapon considered a “firearm.” It is the central chassis that holds the mechanical parts and carries the serial number. All other parts—barrels, triggers, slides—are just unregulated scrap metal or plastic.
The “ghost gun” industry relies on selling “80% frames”:
- The Concept: Manufacturers (such as Polymer80) sell frames that are only about 80% finished.
- The Legal Loophole: Because the frame is incomplete (e.g., the trigger cavity isn’t hollowed out, or pin holes aren’t drilled), the ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives) generally does not classify it as a firearm. It is technically just a piece of plastic or metal.
- The Purchase: Because it is not a firearm, it can be bought online without a background check and has no serial number.
- The Assembly: The buyer receives the kit, which usually includes a “jig” (a template). Using basic tools like a drill, the buyer finishes the remaining 20% of the work.
- The Result: Once the drilling is done, the buyer installs the remaining parts (barrel, trigger, slide). The result is a fully functional firearm.
Why the Name “Ghost”?
The defining characteristic of these weapons is untraceability.
When a crime is committed with a factory-made firearm, law enforcement can use the serial number to trace the weapon from the manufacturer to the distributor and finally to the original retail purchaser. This “chain of custody” is a primary investigative tool.
With a ghost gun, that chain never begins. Since the frame was never serialized and the buyer built it in private, the weapon has no paper trail. If found at a crime scene, it is a regulatory “ghost”—offering no clues about where it came from or who owns it.