By then, the plans had already been downloaded more than 100,000 times and they remain available on file-sharing websites, he said.
"If you want to do this, it's plainly obvious there's no one standing between you, your computer and your 3-D printer. Anyone can make this gun," Wilson said Monday.
Lawmakers and law enforcement officials alike have long been concerned that technological advances could allow for the production of guns that don't have any metal, first passing the ban on such weapons in 1988 under President Ronald Reagan. It has been renewed twice since then.
Today 3-D printers can spray repeated, thin layers of plastic or other materials to create objects from toys to automobile parts to medical devices. They are being used increasingly by companies, researchers and hobbyists, and the technology is constantly improving.
But printing a gun isn't cheap. According to the Bureau of Alcohol, Tobacco, Firearms and Explosives said 3-D printers can cost anywhere from $1,000 to $500,000, though they can be rented. A traditional handgun can cost far less.
It's also unclear how effective such a gun can be.
ATF tested two plastic guns from different plastics earlier this year, and one of the weapons exploded when it was fired. The second one shot off eight rounds before ATF stopped the test.
Among the chief concerns from law enforcement and law makers has been that a 3-D printed gun, made of plastic or other materials, could be easily slipped through metal detector at a courthouse or other such facilities.
New technologies being used at airports, including back-scatter X-ray machines, are designed to detect non-metallic anomalies, such as liquids and potentially plastic guns.
While the NRA didn't oppose extending the current law, it has opposed expanding it, including applying the law "to magazines, gun parts, or the development of new technologies."