Learning to make a so-called ghost gun — an untraceable, unregistered firearm without a serial number — could soon become much easier.
The United States last month agreed to allow a Texas man to distribute online instruction manuals for a pistol that could be made by anyone with access to a 3-D printer. The man, Cody Wilson, had sued the government in 2015 after the State Department forced him to take down the instructions because they violated export laws.
Mr. Wilson, who is well known in anarchist and gun-rights communities, complained that his right to free speech was being stifled and that he was sharing computer code, not actual guns.
The case was settled on June 29, and Mr. Wilson gave The New York Times a copy of the agreement this week. The settlement states that 3-D printing tutorials are approved “for public release (i.e. unlimited distribution) in any form.”
The government also agreed to pay nearly $40,000 of Mr. Wilson’s legal fees.
The willingness to resolve the case — after the government had won some lower court judgments — has raised alarms among gun-control advocates, who said it would make it easier for felons and others to get firearms. Some critics said it suggested close ties between the Trump administration and gun-ownership advocates, this week filing requests for documents that might explain why the government agreed to settle.
The administration “capitulated in a case it had won at every step of the way,” said J. Adam Skaggs, the chief counsel for the Giffords Law Center to Prevent Gun Violence. “This isn’t a case where the underlying facts of the law changed. The only thing that changed was the administration.”
Mr. Wilson’s organization, Defense Distributed, will repost its online guides on Aug. 1, when “the age of the downloadable gun formally begins,” according to its website. The files will include plans to make a variety of firearms using 3-D printers, including for AR-15-style rifles, which have been used in several mass shootings.
Mr. Wilson said the settlement would allow gunmaking enthusiasts to come out from the shadows. Copies of his plans have circulated on the so-called dark web since his site went down.
“I can see how it would attract more people and maybe lessen the tactic of having to hide your identity,” Mr. Wilson said of the settlement in an interview. “It’s not a huge space right now, but I do know that it’s only going to accelerate things.”
But as the “landmark settlement” brings ghost gun instructions out into the open, it could also give felons and domestic abusers access to firearms that background checks would otherwise block them from owning, said Adam Winkler, a law professor at the University of California, Los Angeles.
“The current laws are already difficult to enforce — they’re historically not especially powerful, and they’re riddled with loopholes — and this will just make those laws easier to evade,” Mr. Winkler said. “It not only allows this tech to flourish out of the underground but gives it legal sanction.”
Some saw the settlement as proof that the Trump administration wanted to further deregulate the gun industry and increase access to firearms. This year, the administration proposed a rule change that would revise and streamline the process for exporting consumer firearms and related technical information, including tutorials for 3-D printed designs.
The change, long sought by firearms manufacturers, would shift jurisdiction of certain items from the State Department to the Commerce Department, which uses a simpler licensing procedure for exports.
On Thursday and Friday, the Brady Center to Prevent Gun Violence filed requests under the Freedom of Information Act for any documents showing how the government decided on the settlement over printable firearms, and whether organizations like the National Rifle Association or the National Shooting Sports Foundation were involved.
Neither trade group commented for this article, but some gun advocates said Mr. Trump has been less helpful toward the firearms industry than he had suggested he would be.
Mr. Wilson also said that “there has not been a pro-gun streak” under Mr. Trump’s Justice Department, though he praised the nomination of Judge Brett M. Kavanaugh, who is seen as a champion of Second Amendment rights, to the Supreme Court.
“Trump will go to the N.R.A. and be like, ‘I’m your greatest friend,’ but unfortunately his D.O.J. has fought gun cases tooth and nail in the courts,” he said.
Mr. Wilson clashed with the government in 2013 after he successfully printed a mostly plastic handgun — a tech-focused twist on a longstanding and generally legal tradition of do-it-yourself gunmaking that has included AR-15 crafting parties in enthusiasts’ garages. His creation inspired Philadelphia to pass legislation banning the use of 3-D printers to manufacture firearms.
After Mr. Wilson posted online blueprints for the gun, they were downloaded more than 100,000 times within a few days, and later appeared on other websites and file-sharing services.
The State Department quickly caught wind of the files and demanded that Mr. Wilson remove them, saying that they violated export regulations dealing with sensitive military hardware and technology.
Mr. Wilson capitulated, and after two years paired up with the Second Amendment Foundation to file his lawsuit. A Federal District Court judge denied his request for a preliminary injunction against the State Department, a decision that an appellate court upheld. The Supreme Court declined to hear the case.
In a statement, the State Department said the settlement with Mr. Wilson was voluntary and “entered into following negotiations,” adding that “the court did not rule in favor of the plaintiffs in this case.”
To raise money for his legal defense, he said, he sold milling machines that can read digital design files and stamp out metal gun parts. Proceeds from the so-called Ghost Gunner machines, which cost $1,675 each, are used to run his organization, he said.
Ghost guns, by their nature, are difficult to track.
Guns manufactured for sale feature a serial number on the receiver, which houses the firing mechanism. But unfinished frames known as “80 percent” receivers can be easily purchased, completed with machinery like the Ghost Gunner and then combined with the remaining parts of the firearm, which are readily available online and at gun shows.
Several local governments have stepped up efforts to restrict such guns. On Thursday, the attorney general of New Jersey sent cease-and-desist letters to companies that make and sell kits with partly built firearms in the state.
But with the government adjusting the export rules that first sparked the case, Mr. Wilson will be able to freely publish blueprints for 3-D printers, said Alan M. Gottlieb, the founder of the Second Amendment Foundation, in a statement.
“Not only is this a First Amendment victory for free speech,” he said, “it also is a devastating blow to the gun prohibition lobby.”