If you thought it was impressive and unsettling when Defense Distributed manufactured the "Liberator," a functional 3-D printed plastic gun, earlier this month with the help of anĀ $8,000 Stratasys (NASDAQ:SSYS) industrial 3-D printer, wait until you see what a hobbyist created with an off-the-shelf, $1,725 consumer 3-D printer and $25 of materials.

Dubbed the "Lulz Liberator", the gun's parts were printed on a $1,725 Lulzbot AO-101 3-D printer and the plastic barrel lasted eight rounds before needing to be replaced for the ninth fire. Surprisingly, the at-home version of this gun preformed better than the original Liberator, which needed a replacement barrel after each fire. The anonymous creator of the Lulz Liberator believes that the ABS plastic he used was stronger than the plastic used in making the Stratasys Liberator. Even with this advantage, the Lulz Liberator still managed to misfire on several occasions and the spent round had to be removed with a hammer.

Printing Pandora's box
Before the Lulz Liberator was born, some critics dismissed the threat of 3-D printed firearms, citing a lack of practicality and a high barrier of entry associated with purchasing an $8,000 industrial-grade 3-D printer. Naturally, this argument isn't holding as much water now, given the fact that anyone with the right grade of ABS plastic filament and access to a consumer 3-D printer under $2,000 can in theory start making firearms.

Here's looking at you, 3D Systems
Of the publicly traded 3-D printing companies, 3D Systems (NYSE:DDD) has the biggest interest in the consumer-oriented 3-D printing segment with its Cube line of 3-D printers. Starting at a palatable price of $1,299, it's conceivable that these printers could also be capable printing functioning firearms.

However, it's currently unclear what thickness the Lulz Liberator was printed with and if the Cube would suffice. The printer used to create the Lulz Liberator has a minimum print thickness of 75-microns, where the entry-level Cube has a 200-micron print thickness. The Cube X, 3D Systems' higher-end consumer-oriented 3-D printer aimed at serious enthusiasts, has a minimum layer thickness of 100 microns, which also may not be a fine enough resolution for this application. Additionally, the Cube printers use a proprietary blend of ABS plastic, which may not be as strong as the ABS used in the demonstration.

The bigger picture
As 3-D printing continues to proliferate throughout the world, it's going to prove more difficult to stop the underground movement to create homemade firearms, despite its potentially dark implications. Perhaps if government regulation is really in the cards, maybe the angle is to control ammunition more? Actually, it's a little late for that.

In the end, the Internet and at-home 3-D printing is proving to be an extremely powerful, disruptive, and potentially unsettling idea.

Motley Fool contributor Steve Heller owns shares of 3D Systems. The Motley Fool recommends 3D Systems and Stratasys. The Motley Fool owns shares of 3D Systems and Stratasys and has the following options: Short Jan 2014 $36 Calls on 3D Systems and Short Jan 2014 $20 Puts on 3D Systems. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.