He then published his blueprints along with those for a range of other guns on his personal website. The Planet Money podcast reports that he even published schematics for an anti-aircraft warhead.
Within a few days, the site attracted 100,000 visitors from all over the world.
The State Department Office of Defense Trade Controls Compliance demanded the website be taken down because it contravened laws relating to the export of firearms.
But by that stage, it's anyone's guess how many people had seen the site and potentially shared the schematics with their friends.
The question then is whether access to these schematics poses a risk to a country like New Zealand, which has relatively strict gun laws.
Johan Potgieter, an associate professor in mechatronics at Massey University, told the Herald New Zealanders don't have anything to be concerned about at this stage.
He said the cost of a 3D printer capable of creating a gun remains too prohibitive to make a viable option for a person intent on killing others.
"A good 3D printer will cost you around $40,000," Potgieter said.
He said that lower-grade 3D printers would, at best, produce a gun capable of one shot before being destroyed.
However, given that technology is moving quickly and becoming more affordable, Potgieter said it is something New Zealand should keep an eye on.
He stressed that there are far easier ways to cause harm than 3D printing a weapon with a massively expensive piece of equipment.
He lists knives, cars and even bricks as options already at the disposal of people interested in doing harm to others.
"3D printing a gun is just too much effort compared to these," he said.
Potgieter says rampant violence, such as that we see in the United States, is a societal issue, which needs to be fixed.
Asked about the danger of having easy access to the schematics to make weaponry, Potgieter said this is nothing new.
The Anarchist's Cookbook, first published in 1971, is perhaps the best example of this, serving as a manual for creating weapons, bombs and illicit drugs.
While the book has been linked to a number of atrocities over the years, Potgieter says that most people bent on harming others generally don't go through the arduous steps of making a weapon from scratch.
"Real guns are still too easy and too cheap to get," Potgieter says in explaining why 3D printed arms aren't an immediate concern.