Monday, August 20, 2018

re: 3d printed guns (links and photos)

Guns, Government, and 3d Printing...

Earlier this month Defense Distributed won victory regarding the legal right to distribute files - and was subsequently cock-blocked by a federal judge on behalf of anti-rights organizations.  Although DD doesn't actually have files on their website, you can still definitely download receiver files off GrabCad and any number of other websites - and it's been that way for several years.


Tax dollars at work
Anonymous Marine building guns 'n shit.
Coincidentally, the Marines invited me to attend a short 3 day training class on 3d printing at their machine shop in Twentynine Palms.  I never gave much thought to 3d printers and their capabilities before. In terms of firearms design - every time I looked at the Defense Distributed "Liberator" pistol I just saw a gimmicky gun that would blow up after several shots. But I don't think the Liberator was ever supposed to be a serious design, but rather to prove a point. Besides that, accessories and prototyping firearms is where 3D printing is really more useful.

Marine at a milling machine.
I was actually at the machineshop on behalf of my fellow hospital Corpsman to get some ideas on how we could use something like this for medical purposes and possibly purchase and use it on deployment.  Though honestly, I can't think of anything entirely useful.  Things that might be useful: replacement buckles for the Talon Litter straps and medical bags that are always breaking; holders, holsters, latches, and other mostly pointless doodads that could probably be improvised quicker with 550 cord, duct tape and carabiners.  I've seen videos of hospitals that were using 3D printers to create replacement bones, prosthetics, casts, joints, and other actually useful stuff - but for battlefield medicine I don't really see a need for a 3d printer.

The Marines swore it was useful, though - Take a nitrogen pumping system that cost $800, for example. The handle was made from a cheap plastic that would seldom break, however the company that makes these systems would not sell the handle seperately, so the shop would print a replacement handle for next to nothing. Having to machine it from metal on the milling machines would have been a waste of time and resources, but once you reverse engineer it in CAD you don't have to waste valuable man-hours on it again - just print it and go on a smoke break or do something productive while you wait. Having the capability to replicate and produce the handle saved the battalion $800. Mostly 'small' cost savings that would save money over a long period of time and pay for the actual printer cost after several prints. The printer being used was a Lulzbot 6, approximately $2000 - $2500.

3d printed M16A2 carry handleThe shop had a table full of junk that they printed out to show off the capabilities - doodads, toys, statues, gun parts. There was an M16-A2 carryhandle, an M4 handguard, rail protectors and an M249 handguard. There were replacement parts for a drone - wings, propellers and main housing. There was a 2x2 foot vent cover, but it would have been quicker to make it using a laser CNC on a piece of sheet metal, but it was more of a test than anything actually useful.

The corporal in charge of this program was pretty cool.  All he talked about was guns and gun accessories.  Prototypes, parts, unserialized receivers - anything but a rifled barrel could be built on the CNC and manual milling machines there.  They had a massive 4 foot cubed 3D Printer that stood about 7x7 feet total in it's own trailer.  He used the machineshop after working hours to produce all sorts of naughty stuff.   We had a good talk about guns, militias, survivalism, weapons caches, and how great Trump was.  I should have married him.

Thirty minutes learning in CAD and a few personal prototypes of my own and I created my first thing.  A bottom plate for a Browning 1919 dress-up kit that I am designing for a belt-fed AR15, which I talked briefly about here.  I could have just imported it from my own already existing files, but I wanted to learn the fancy software that they were using, so I rebuilt it from scratch.  Oh and this thing doubles as a tablet holder, so if anyone asks what it is - it's a tablet holder.  Yep.  A tablet holder.
Mounted AR15 lower plate test
The purple thing is the item in question.
The inner distance between the walls should have been 1.55" and the slotted grooves would fit the 0.187" receiver side plates. The actual printout is not entirely dimensionally accurate, but it's within +/- 0.01" which I think was pleasantly surprising.

It took several tries with the print. The first time the machine spazzed out midway because the air condition unit kicked on and cooled the machine directly under a vent, causing the plastic to cool in the nozzle and clog up. I had another fuckup when we left the printer on overnight and the spool tangled up and jammed.

The third time was the charm.  It took about one and a half hours for this bottom plate. The in-fill was at 50%, which means that most of the inside was just hollow with 50% supporting material.  I looked at it and thought "hey, neat," and ended up adding it to the already growing pile of 3d printed stuff they had accumulating on the table.  I actually didn't design the rivet holes in it and I couldn't drill through it because there would be air pockets inside between the support material.

But it seemed pretty solid for a proof-of-concept.  Just enough rigidity to hold together side plates and assemble a non-firing prototype.  It would probably get destroyed with light use and man-handling - a static display model basically.  With stronger polymer and 100% in-fill, this could be a functioning component.

The class was pretty much everything I had thought it would be and more. I am convinced that I now need a 3d printer.  Below is an experimental bolt action gun that uses an AR15 bolt and extension that caught my attention.  The carrier is custom made to allow hand-cycling using the bolt and locking lugs of the extension, operating like a traditional bolt action.  I saved the pictures and I am unsure who actually created this, but the discussion was on a thread at TheFirearmsBlog here which seems to have been deleted for some reason.

bolt action ar15 thingy
Bolt action parts.

bolt action ar15 thingy
Bolt-action based on the AR15
There's even a VZ-61 semi-auto skorpion lower receiver on GrabCad right now.  This is really interesting because VZ-61 parts kits are readily available and there are currently no receivers available anywhere.  On top of that, this design has been modified for use with Sig arm braces and has a reinforced backplate for added durability.

3d printed vz-61 skorpion
3d printed VZ-61 Skorpion receiver.
3d printed files of interest:
3d Printed stuff archives.  There's dozens of sites that just list a bunch of user submitted 3d stuff.  These are ones that I've used or that others have recommended to me.
  • Thingiverse - Free stuff that you can download and print right now.  Not necessarily gun stuff, but pretty useful.
  • Yeggi - A database that links to other 3d printed website.
  • My Mini Factory - Haven't used it, but I hear good stuff about this.
  • PrintedFirearm.com - Exactly what it says on the box.
  • GrabCad - Another good source of stuff.  Lots of gun-related stuff.

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