Gun enthusiasts and hobbyists have long been building their own firearms by purchasing lower receivers or kits and other parts needed to assemble a firearm.
The lower receiver is a small block of metal about the size of a deck of cards where the trigger mechanism is housed and where bullets pass through. A gun cannot function without it. A finished lower receiver is the piece of the firearm regulated by federal law and must contain a serial number stamped into it.
Technology today and the hundreds or even thousands of websites selling lower receivers, kits, and parts over the internet makes it even easier. There are no background checks required to purchase these lower receivers or kits.
There are no federal restrictions on an individual making a firearm for personal use, so long as it does not violate the National Firearms Act (NFA), according to the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF).
The ATF has long held that items such as receiver blanks, “castings” or “machined bodies” in which the fire-control cavity area is completely solid and un-machined have not reached the “stage of manufacture” which would result in the classification of a firearm per the Gun Control Act of 1934 (GCA). That stage is “80 percent complete.” ATF regulations hold that receiver blanks that do not meet the definition of a “firearm” are not subject to regulation under the GCA.
Furthermore, under federal law, no serial numbers are needed on firearms that are built for personal use, making them untraceable by law enforcement.
By leaving the lower receiver unfinished— meaning only partially drilled — it fails to meet the ATF’s requirement of being more than 80 percent complete and is therefore not considered a “firearm” subject to regulations. Buyers can finish the receivers at home by finishing the drilling.
The ATF refers to such guns as unfinished receivers, though they’re also called 80 percent receivers, home built firearms, or “ghost guns.”
And it’s all perfectly legal.
These self-assembled and untraceable “ghost guns” are becoming increasingly more popular amongst gun enthusiasts across the country and is becoming big business for parts manufacturers and for dealers selling kits.
Elite Custom Railing in Holly Hill, Florida, for example, specializes in unfinished lower receivers for a do-it-yourself AR-15. A company spokesperson said they sell between 100 and 150 lower receivers each day.
It is just one of six companies in Volusia County alone engaged in manufacturing and/or selling kits or unfinished receivers that allow buyers to assemble military-style, semi-automatic rifles at home.
Another Volusia County company, Stone Mountain Gold ‘n Guns in DeLand, will sell the “80% receivers” to a customer only in person and not over the internet as others in the county do. A manager said he will complete the sale only if he feels comfortable with the person buying the receiver. Stone Mountain sells about 20 a month, according to the manager.
The ATF and some law enforcement agencies have expressed a concern about these homemade firearms, believing that the availability of the untraceable receivers will encourage criminals and terrorists to start building their own weapons.
Port Orange Police Chief Thomas Grimaldi said in an interview in the Daytona Beach News-Journal, “We’re making it easy for the criminals. I have a concern — a huge concern over that.”
Mary Salter, ATF Tampa Field Division public information officer, believes some criminals are purchasing non-serialized and therefore untraceable firearms because their intent is to commit crimes.
“ATF, and law enforcement, in general is seeing homemade firearms without serial numbers at crime scenes,” Salter said. “Tracing firearms found at crime scenes to the original purchaser is a valuable tool in law enforcement,” Salter added. “When a homemade firearm is found at a crime scene, investigators are left with a dead end, where a trace of a firearm may generate valuable investigative leads.”
“With advancements in technology in regards to 3D printers,” Salter said, “CNC milling machines, and the availability of receiver blanks, it has become much easier for a person to build a firearm. “When a “homemade firearm is found at a crime scene, it means investigators are virtually left with a dead end,” said Salter.
And in California, Graham Barlowe, resident agent in charge at the ATF’s Sacramento Field Office, said he started seeing crimes involving untraceable guns about two years ago. In November of this year, Barlowe’s undercover agents arrested eight men for manufacturing and selling illegal firearms, seizing about 90 un-serialized firearms out of the more than 230 illegal firearms found. His agents have also found electronic mills that carve a complete receiver in 12 minutes.
“It is one of the biggest problems in Northern California for our office, if not the biggest problem,” Barlowe says. He estimates that his office has seized about 500 un-serialized receivers since 2013.
The Santa Monica shooter, John Zawahri, used a rifle made from parts he purchased online to kill himself and five others on June 7, 2013.

And in neighboring Arizona, between 2009 to 2011, ATF reported that it seized 191 of the 80 percent receivers in Tucson that were headed to Mexico to be assembled, possibly by cartels.
In Florida, law enforcement officials claim the unregistered guns can make it easy for criminals to arm themselves with untraceable weapons.
However, others disagree with that assessment, claiming the skill and equipment necessary to build the firearms is anything but easy and, therefore, makes this approach more costly and time-consuming than simply acquiring an already completed firearm. A milling machine (or at least a milling guide kit), for example, can cost around $1,500, and it could take weeks to complete an AR-15 kit.
And to complete an unfinished lower receiver, a person must carefully mill or drill out a portion of the inside of the receiver, which can take many painstaking hours. Without a properly milled lower received, a functioning firearm would be impossible to produce.
Many believe manufacturing a homemade weapon is generally too costly, too troublesome, and too expensive for criminals.
Furthermore, FBI statistics indicate semi-automatic weapons are used in less than one percent of crimes in the U.S. Most criminals use handguns, and most guns used in crimes are stolen. Criminals looking to buy a weapon can get them from private sales without a background check and do not have to go through the trouble and expense of building their own rifle.
Rob Dunaway, President of American Spirit Arms in Scottsdale, Arizona, says most of the customers who buy the incomplete receivers are people who like to personalize their semi-automatic rifle and or more worried about changes to the gun laws.
“Some people buy them to store them for potential future use,” Dunaway said.
Previous attempts to regulate “ghost guns” in California failed, when a bill that would have allowed the manufacture or assembly of homemade weapons but required the makers to first apply to the state Department of Justice for a serial number that would be given only after the applicants underwent a background check, was vetoed by Governor Jerry Brown in 2014.
However, earlier this year, Gov. Brown did sign a bill requiring people who build guns from these 80% receivers to register them and get a serial number. That law takes full effect in 2019. — by Michael Wisdom, Senior Contributing Editor, Texas & U.S. Law Shield Blog