The ruling overrides a previous settlement between the US government and Texan organisation Defense Distributed that made it legal to post 3D printable gun plans on the internet.

Just hours before the 1 August deadline when the guns were set to be uploaded and made available online, Judge Robert Lasnik of the United States District court handed down a nationwide injunction preventing the blueprints for the weapons from being published online.

“There is a possibility of irreparable harm because of the way these guns can be made,” Lasnik said.

The weapons would be untraceable and can be manufactured cheaply using a Lego-like plastic. Actor and activist Alyssa Milano recently wrote an opinion piece arguing the fully functional 3D-printed guns could be obtained, for example, by a domestic violence abuser who has been barred from legally purchasing a gun.

The so-called ‘ghost guns’ would totally circumvent background checks and firearm registration.

The Texas-based non-profit Defense Distributed was arguing that any ban on the 3D-printed guns would be an unconstitutional restriction on free speech and the right to bear arms. Justice Lasnik raised the possibility of criminals and terrorist groups using the plans to make their own weapons.

Defense Distributed hails “the age of the downloadable gun” on its website. The site also notes that users would be able to manufacture their own guns from its design files without any experience or prior knowledge of CNC (computer numerical control).

It offers users the opportunity to “Legally manufacture unserialized rifles and pistols in the comfort and privacy of home.”

Shortly after the injunction was handed down, US President Donald Trump offered a gnomic comment on the issue on Twitter.

“Already spoke to the NRA,” Trump reported. “Doesn’t seem to make much sense!”

Eight states sought an injunction against the ghost gun blueprints

The Attorney-Generals from eight states joined the suit to stop organisations and individuals such as Defense Distributed from publishing the blueprints.

Washington Attorney-General Bob Ferguson told Anderson Cooper 360 that the ruling had made it unlawful to post the relevant information about making the guns.

“What it means is if anyone posts this information online, they are in violation of federal law and can suffer very serious consequences,” Ferguson said.

Defense Distributed founder Cody Wilson said the site has disabled downloads pending a review of the injunction.

Alan Gottlieb, co-founder of the Second Amendment Foundation, told CNN’s Cuomo Prime Time that the First Amendment right to free speech should be interpreted to uphold the Second Amendment right to bear arms.

“If you’re allowed to own a firearm in your own home, you should be able to make the firearm in your own home if you can’t buy one locally because of crazy restrictions,” he said.

Maura Healey, Attorney-general of Massachusetts, said the potential availability of 3D-printed ghost guns presented a serious public safety issue. “It puts our residents at risk of harm,” she said.

“It puts weapons into the hands of people who otherwise wouldn’t be able to acquire them.”

The legality of 3D-printed guns

Officials in the Obama administration had blocked Defense Distributed from making the downloadable plans for firearms available on the grounds that it violated export laws which prohibited the distribution of firearms to other countries.

Under the Trump administration, the State Department reversed this decision in June 2018 after deciding the publication of the blueprints did not breach the export controls on firearms which were designed to prevent new military technology being sold to unfriendly nations.

Huffington Post reported that the blueprints had been downloaded more than thousands of times as of 31 July local time. ‘The Liberator’ a single-shot .300 caliber handgun was the most popular download with more than 4,500 downloads for this model alone.

Avery Gardiner, co-president of the anti-gun violence non-government organisation Brady Campaign, said the weapons are incredibly dangerous. “It is immediately obvious to anyone who looks at this issue that 3D-printed guns are nothing short of a menace to society, and we are thrilled that the court ruled in this manner.

“The efforts of these Attorneys General throughout the nation have helped strike a powerful blow against the scourge of 3D-printed guns, but we know this fight is not yet over. We will continue to do everything in our power to make sure that this temporary halt in publication becomes a permanent one.”

Cody R. Wilson, a self-described crypto-anarchist, is expected to continue the legal battle over the guns.