In its continuing mission to build a “Wiki Weapon,” Defense Distributed has 3D printed the lower receiver of an AR-15 assault rifle and tested it to failure — on video (embedded below). The printed part only survives the firing of six shots, but for a first attempt that’s quite impressive. And hey, it’s a plastic gun.

We covered the first 3D-printed gun back in July. The Defense Distributed group sprung up soon after, with the purpose of creating an open-source gun — a Wiki Weapon — that can be downloaded from the internet and printed out. The Defense Distributed manifesto mainly quotes a bunch of historical figures who supported the right to bear arms. DefDist (its nickname) is seeking a gun manufacturing license from the ATF, but so far the feds haven’t responded.

Unperturbed, DefDist started down the road by renting an advanced 3D printing machine from Stratasys — but when the company found out what its machine was being used for, it was repossessed. DefDist has now obtained a 3D printer from Objet, which seemingly has a more libertarian mindset. The group then downloaded HaveBlue’s original AR-15 lower receiver from Thingiverse, printed it out on the Objet printer using ABS-like Digital Material, screwed it into an AR-57 upper receiver, loaded up some FN 5.7x28mm ammo, and headed to the range.

As you can see in the video above, after six shots the lower receiver quite literally (and humorously) falls to pieces. In this case, it seems like the ring thread that screws onto the upper receiver was fractured by the recoil forces. The DefDist team will now make various modifications to HaveBlue’s design, such as making it more rugged and improving the trigger guard, and then upload the new design to Thingiverse. Thus the open-source circle is complete!

Suffice it to say, the idea that people can download and print their own guns is rather scary. In current law, the lower receiver is the firearm — the lower receiver is the part that is regulated, and the part that bears the serial number. The ability to print your own lower receiver could allow people without gun licenses, or revoked licenses, to obtain a gun.

For now, of course, we should be pacified by the knowledge that consumer-grade printers draw the line at plastic — and it’s unlikely that gun barrels, springs, and other assorted parts can be fashioned out of plastic. In an industrial setting, though, 3D printing processes such as selective laser melting/sintering (SLM, SLS) are being used to create incredibly rugged parts out of metal. NASA, for example, is producing rocket parts with 3D printing. It is really only a matter of time until everyone has the hardware at home to print a complete firearm — or, well, any weapon really.

Now read: 3D printing: a replicator and teleporter in every home