Last week, Cody Wilson fired a shot heard around the world.

After spending a year trying to manufacture--with his own 3D printer--the Liberator, a plastic handgun that fires .380 caliber bullets, Wilson proved it worked at a gun range near Austin, Texas. 

Pundits such as Bill Maher waded into the ensuing debate, espousing the obvious dangers and ethical issues of such weapons, while others cringed at the notion of invisible guns. (The Liberator doesn't set off a metal detector.) If anyone at any time could print a 3D handgun, who's to stop the country from dissolving into anarchy?

3D Printer Makers Recognize the Risk

3D printer manufacturers have been quick to distance from Wilson and his Austin-based company, Defense Distributed. With sound bites like "our ambition was to kill the spirit of gun control entirely" and government is not "a benign institution," he's been nothing less than a polarizing figure, especially for entrepreneurs who play a role in bringing his innovation to market. 

Crowdfunding site Indiegogo dropped Defense Distributed's gun printing project in response to complaints. After the Sandy Hook massacre, Makerbot yanked all Defense Distributed's CAD (computer-aided design) files from "Thingiverse," a clearinghouse site for the 3D printer community.

Just this past weekend, Internet entrepreneur and advocate Kim Dotcom removed gun files from his Mega file-storage service upon news the U.S. State Department asked Defense Distributed to pull files from its site. As Dotcom's lawyer Ira P. Rothken told PC World, "... we are dealing with an issue of first impression regarding printing plans for 3D guns."

It may be difficult for companies to steer clear of 3D-printing misuse, though.

The market for 3D printers has quickly picked up--research firm Wohlers Associates said 6,500 large professional-grade printers sold in 2011, along with 23,000 cheaper, "personal" machines.

What's more, printers are expected to drop in price, and the market is projected to more than double by 2020, with sales topping $5 billion a year. Already, Staples has agreed to begin selling the devices in its national stores.

A Serious Ethical Conundrum 

Is a 3D printer maker responsible if someone uses its printer to manufacture a gun that is then used to kill someone?

"If you help people to make terrorist bombs, you are morally and partially responsible for the damage that they do," warns Kirk O. Hamson, a business ethicist and executive director for the Markkula Center for Applied Ethics at Santa Clara University in California.

A self-regulatory process or standard may be required. Perhaps 3D printer manufacturers should spearhead a "collective voluntary effort" to save face as the drama unfolds--and perhaps help avoid the need for broader government regulation. Everyday copy machines--which can be used to produce high quality counterfeit bills, for instance--aren't regulated.

3D-printer makers could sell selectively. "There's a responsibility to take some notice, or perhaps even screen the purchasers of your 3D devices," says Hamson. "You don't want to sell one to the Mexican drug lords. But you may sell it to a reputable channel, and then have it diverted later."

It may even be wise to track down the use of a particular machine, after it's been sold, and devise a more sophisticated device that can discover "invisible" items shaped in certain ways, like a plastic gun. Hamson adds: "One would hope that these manufacturers have thought through all the improper ways the technology can be used and at least asked the question, 'Is there any way for us to prevent the misuse?'"

3D printer makers 3D Systems and Makerbot did not return calls for comment.

For now at least, perhaps Americans can rest (sort of) easy knowing actual guns--the kind you can buy in a store--outnumber the fake ones by nearly 5 million. Also, those ownership rates are down. According to a report from the Violence Policy Center, only one out of five Americans report personally owning a gun.