Wiki Weapon Project Test-Fires a (Partly) 3D-Printed Rifle

MrSeb writes "In its continuing mission to build a 'Wiki Weapon,' Defense Distributed has 3D printed the lower receiver of an AR-15 and tested it to failure. 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. Slashdot first covered 3D-printed guns 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. 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." Sensible ammo choice; 5.7x28mm produces less recoil than the AR-15's conventional 5.56mm. I wonder how many of the upper's components, too, can one day be readily replaced with home-printable parts — for AR-15 style rifles, the upper assembly is where the gun's barrel lives, while the lower assembly (the part printed and tested here) is the legally controlled part of the firearm.

Comments

Did He Really Just Pull That Up To His Face?

[eldavojohn]

And hey, it's a plastic gun.

No, it's not. It's not even close to that. It's a plastic lower receiver with the rest of the gun being not plastic.

As someone who's taken gun safety, I'm shocked he put himself at risk to test this. Making a shooting bench is fairly trivial. Automating a trigger pulling mechanism is a little more difficult but would require very basic knowledge. I'm surprised someone with access to a 3D printer would be stupid enough to pull a plastic lower receiver up to his face, put his hand on it and pull the trigger until it failed. In gun safety they show you what even an obstructed barrel can result in when firing a gun. That action mechanism would basically become shrapnel for your right hand, left forearm and face.

If these guys want to be taken seriously, they probably should 3D print something that will prevent them from winning a Darwin award.

Re:Did He Really Just Pull That Up To His Face?

[swb]

Well, there's some risk, but it's pretty minimal. The upper receiver is likely metal, and the upper receiver holds the bolt and the barrel and chamber.

It's hard to see what kind of problem you would have if the lower failed -- feed problem with a dropped magazine? Broken trigger guard, or just some larger mechanical failure if the lower itself cracked or split?

None of these would result in a gun blowing up in your face as the cartridge is fired in the chamber which is an integral part of the barrel and connected mechanically to the upper receiver.

It seems like a good machinist's face shield and a pair of gloves would be more than adequate protection for the risks involved.

Re:Did He Really Just Pull That Up To His Face?

[need4mospd]

The only purpose of a hood is to keep stuff from getting in the engine bay and improve aerodynamics. If you think it adds structural integrity to the vehicle, I suggest you spend a little more time under the hood. Most hoods are attached at two points by weak hinges, real structural there. Not to mention, a common hood material is fiberglass which breaks up into shards fairly easy.

Re:Did He Really Just Pull That Up To His Face?

[Anonymous Coward]

Well...
As a person who actually builds ARs as a hobby let me follow up. The lower receiver is also where the buffer tube is attached. The buffer and buffer spring are absorbing the blow back of the bolt carrier group and is responsible for returning it to battery position. The point at which the buffer tube meets the lower receiver is a potential point of failure since the receiver is not aluminum. This also happens to be right about where your face is. If it breaks loose chances are the rifle will simply fail to cycle at all. Although if it breaks loose and you fire a second round you may end up with a BCG slamming into a broken buffer tube and having part of it lodged into the side of your face. Even if the potential for failure is small it does exist. Maybe it is just me but until you work out the kinks placing your face next to it is in fact extremely unsafe, face shield or not. One solution to this point of failure is to embed a threaded aluminum collar into the printed piece so the buffer tube had solid threads to anchor to.

Re:Did He Really Just Pull That Up To His Face?

[GigsVT]

On some guns the upper section is considered the firearm. It depends on the gun. On the AR-15 it's likely the lower because the lower houses the fire control group (trigger/sear/hammer), which defines important traits such as whether the gun is full auto or not.

The plus side to this is that you can often take a fully automatic lower receiver and use it with different uppers to effectively create different kinds of fully auto guns without needing to get separate tax stamps and avoiding the 1986 prohibition on building new machine guns (with some legal caveats, do the research if you intend to do this).

Object and Stratasys have merged

[Anonymous Coward]

Object and Stratasys have completed their merger yesterday, so we'll see about that "libertarian mindset"...

Re:Legality?

[Baloroth]

Since the lower receiver is the "regulated" part of the AR-15 (the part that the ATF considers to be the actual gun), isn't think rather illegal?

Home-made rifles are completely legal, you just can't sell or otherwise distribute them. The plans for them, on the other hand, you can distribute, hence the project.

not that interesting or new

[Trepidity]

Because of the weapon's design, the receiver on an AR-15 is a notoriously easy part to produce, and has been possible to produce on low-end CNC mills for years. It's not in any way the most difficult part of the weapon to produce; it's just the outer housing within which the actual functional parts are located. Sort of like printing a computer case but not printing what goes inside the case.