The 3-D printable Liberator pistol invented by Defense Distributed in 2013 Wikimedia

The age of 3-D printing in carbon fiber has hardly arrived. But the controversy over 3-D printing carbon fiber guns is well under way.

Starting in the second half of last year, 3-D printing startup MarkForged has been shipping the Mark One, a device it advertises as the world’s first 3-D printer that prints carbon fiber; The Mark One digitally fabricate objects in a material as light as plastic and as strong by some measures as aluminum. But one group isn't about to receive its Mark One order: Defense Distributed, the non-profit political group that invented the first fully 3-D printed gun nearly two years ago.1

Defense Distributed founder Cody Wilson says he pre-ordered the Mark One about a year ago for $8,000, but was told last Friday in a phone call with a MarkForged salesman that the company refuses to sell him one, citing terms of service that disallow private citizens from using the machine to make firearms. So instead, Wilson is offering what he describes as a "bounty" to anyone who can get him MarkForged’s new carbon fiber printer.

“Anyone who’s got access to one, any reseller, any individual or business or entity that can deliver it to me, I will give them fifteen grand,” says Wilson, who has also released a YouTube video advertising his offer. “I’m going to get this printer. I'm going to make a gun with it. And I’m going to make sure everyone knows it was made with a MarkForged printer.”

In a statement to WIRED, MarkForged cited terms of service that "limit experimentation with ordnance to the United States Government and its authorized contractors." In fact, the company's terms of service page doesn't include that statement. But it does reserve the right for the company to refuse sale to anyone, even after an order is placed.

"Our website automatically took Mr. Wilson's pre-order, and we certainly regret that we did not catch this sooner," MarkForged's statement continues. "We are expediting his refund with interest."

Wilson, of course, isn't satisfied with a refund. Defense Distributed's radically libertarian founder—who has said he seeks nothing less than to prove all government regulation irrelevant in the digital era—accuses MarkForged of denying Defense Distributed its printer based on hypocritical politics, given that it's willing to let its machines be used to make weapons for the US military and defense contractors. "They’re happy to sign contracts with [a government contractor like] Boeing. There's Department of Defense money in the mix here," he says. "This isn't about stopping us [from printing a gun.] They're demonstrating which side they're on."

MarkForged is far from the first company to try to disassociate itself from Defense Distributed’s anarchist, gun-loving mission. Indiegogo pulled the group’s initial fundraising campaign in 2012. 3-D printer maker Stratasys refused to rent a printer to the group after it learned what it was being used for. 3-D printing websites like Thingiverse and Shapeways have banned gun components from their collections of CAD models. Even Fedex and UPS have refused to ship a computer-controlled milling machine that Defense Distributed began selling late last year.

Those obstacles didn’t stop Wilson’s gun-making organization from creating and test-firing the Liberator, the world’s first fully 3-D printed firearm, in May, 2013. If the group gets its hands on one of MarkForged’s carbon fiber 3-D printers, it could potentially demonstrate homemade, lethal weapons that are far more durable and practical. MarkForged advertises that its material—plastic polymer laced with carbon fiber strands—is 20 times stiffer than typical 3-D printing plastic and five times stronger, with a higher strength-to-weight ratio than aluminum.

That material could make a firearm that doesn’t crack or deform after a few shots, as the plastic Liberator tends to. Defense Distributed engineer John Sullivan says one of the biggest barriers to the Liberator’s durability has been the expansion of its barrel with every firing. A barrel with strands of carbon fiber wound around it in rings would withstand much greater “hoop stress,” as Sullivan calls it. “The barrel won’t expand. It’s just beautiful,” Sullivan says. “This is a gun machine they’ve made, and we want to make a gun on it.”

Wilson says a more durable barrel is only the beginning. Defense Distributed has been working on 3-D printed carbon fiber gun designs since it pre-ordered MarkForged’s printer last year. “We’re talking about paradigmatically different stuff,” Wilson says. “The gun is entering a new chapter.”

Printing a gun on one of MarkForged’s new carbon fiber printers—if Defense Distributed does obtain one—would be a bit of a stretch from the group’s original goal of making a gun that anyone could download and create on a cheap printer with a click of a mouse. But as 3-D printing evolves and becomes more mainstream, carbon fiber printing is sure to become more accessible, too.

Markforged and other companies’ attempts to publicly distance themselves from that gun-printing won’t prevent it from happening, says Michael Weinberg, a 3-D-printing-focused policy analyst for the non-profit Public Knowledge. “On any sort of scale, this is not particularly sensical,” Weinberg says. “For the printer companies, they don’t have the time or resources or inclination to figure out everything that’s coming out of their machines. That’s an impossible task.”

Weinberg argues that companies like Stratasys or MarkForged refusing business to a group like Defense Distributed is largely a public relations move more than a practical attempt to stymy gun printing. “They’re not thinking ‘now no one will be able to 3d print firearms,'” he says. “They’re thinking, ‘we don’t want to be associated with this high profile example of it.’”

In a marketing video for its new printer, MarkForged founder Greg Mark almost seemed to acknowledge the company’s lack of control over how its customers will use its machines.

“We’ve now enabled you to print carbon fiber,” Mark says in the final line of the video, “And God knows what you’re going to do with it.”

1Correction 3/3/2015: An earlier version of this story incorrectly stated that MarkForged had yet to ship the Mark One. Apologies for the error.