Back in the discussion of 3D printing an AR lower, AmericanLoki requested that I start a new thread once it came time to actually test my printed lower. Well, I finally got around to the testing phase over the past few weeks.

To recap, I have an old Stratasys 3D printer (mid-to-late 90s machine, but works fine) and early last summer I printed a modified version of the lower from cncguns.com (I beefed up the front takedown lugs, bolt hold lugs, and added an integral trigger guard):


(the white one was a 75% scale version of the unmodified lower done as a feasibility test)

I assembled it first into a .22 pistol:


It's had over 200 rounds of .22 through it so far and runs great! To the best of my knowledge, this is the world's first 3D printed firearm to actually be tested, but I have a hard time believing that it really is the first (if anyone can point me to earlier work, it would be much appreciated).

But you guys want more than rimfire, I'm sure. Last weekend I finally re-assembled a .223 upper and gave it a go:



No, it did not blow up into a bazillion tiny plastic shards and maim me for life - I am sorry to have disappointed those of you who foretold doom and gloom.



However, it is giving me feed and extraction issues. As these issues persisted when I switched over to a standard aluminum lower, my problems appear to be with the upper. I'll give it a good cleaning/oiling and try it with some brass cartridges instead. Nevertheless, yes - a 3D printed lower is entirely usable. My model could stand to have a little more material on the buffer tower, but I'm extremely pleased with how well it's working so far. Further details on the construction and intial .22 testing are on my blog:
http://haveblue.org/?p=1041
http://haveblue.org/?p=1321

Also, keep an eye on oryhara's work on printing AR lowers - I think he may soon become the leading authority on the matter: http://rommie.digitalcrowbar.net/wordpress/

This is very cool. Can you give a rough price on what it cost to make? I'm sure there can't be more than a few dollars in actual material in it. I know the machine to make it can't be the cheapest though.

Thats pretty cool

Congratulations on your successful test. I could see this as a way to test new lower designs among other applications. Well done...

Do you have a direct link to the file you used to print your lower?

Thanks
Wes

How long until a 3D printer is considered constructive intent?

TRG

Riddle - the material is ABS plastic. Unfortunately, I don't know which specific resin, but it's similar to SABIC MG47 or Stratasys P400. It is not as strong/durable as a composite lower made of glass filled Nylon 66, but I'm seeing what other materials I might be able to use.

MPD142 - I believe I paid about $100 for the spool of material this was printed from (closeout price), and I used perhaps a tihird to half of the spool. The cheaper (yet more finnicky) PA-747 based material used in RepRaps, Makerbots and the other low cost printers exploding onto the market would bring the cost down to perhaps $10 each worth of material. It will only get cheaper.

phurba and cms81586 - my original idea was to sleeve the holes with brass tubing to act as bushings, but the pins fit in quite nicely, so I'm running it as-is for now. The only wear I'm seeing is a little bit of back-and-forth movement on the hammer pin, only perhaps 10 thou. I'll keep running it and see if it wears further, or if that's the extent of the break-in.

Wangstang - I posted the .STL file on Thingiverse: http://www.thingiverse.com/thing:11770

fatkid35 - I don't believe I've seen acetal (Delrin) available in filament form that could be run through a 3D printer, but it is certainly up to the task of serving as a lower when machined.

I can't wait to see how this develops. What other receivers would be feasible to print in such a machine?

how does it compare, weight wise, to a standard aluminum lower?

Wow!

I once had the chance to see a small company's "rapid prototype" machine and it gave me ideas along these lines. Very cool, keep us posted.

Incredible

Nice! Did you print the threads for the buffer tube, or undersize them and tap yourself?

If so, did you have to play with the toolpaths/raster thickness to get them to come out right?

We just got a pallet of black ABS at work... I might have to... uhh... get the machine set up to use it

Your post makes no sense to me. Are you arguing that because it will become easier to manufacture a firearm that the ATF will no longer try to regulate it? I call BS, and I can see them taking great interest in this thread.