Plastic Brick AR Stock


December 10, 2013, 02:25 PM
Ladies and Gentlemen, ready for testing:

Farmers Fight!

Editor, Feinstein Project

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December 27, 2013, 02:04 AM
Installed, not glued yet:

December 27, 2013, 02:06 AM
Well that's different for sure good luck :D

December 27, 2013, 02:08 AM
Is that Legos?

December 27, 2013, 09:59 AM
LEGO, K'nex, MegaBloks, K'Reo, etc. The buffer tube is a tricky thing to build around.

December 31, 2013, 06:14 PM
I have long suspected that I have no understanding of, or appreciation for, modern "art".

This confirms it... :)

January 1, 2014, 09:19 AM
I like it!

Needs a grip and fore-end as well.

January 1, 2014, 02:25 PM

You're the 2nd person to propose forward handguards. Would you like to take on that effort? I've got to improve my gluing techniques. I fired it for the first time yesterday - the first 20 rounds it held together, but developed a crack between the bricks where I had not glued it. When I fired the next 30, it came completely apart - videos to be posted shortly.

Lesson: Don't rush the gluing schedule just b/c you've been invited to a shoot.

Happy New Year,


January 1, 2014, 10:13 PM
1st 20 rounds - you can see the top endcaps pop off:

Next 29 rounds - what you can't see is the stock completely splits between the unglued bottom & the glued top:

Lots of messy epoxy indicated - and a new buffer tube & bricks...

January 2, 2014, 08:42 AM
Would you like to take on that effort?

only if you're sending me an AR and a big bucket of LEGO!

Sorry, I was enjoying from afar, obviously you have more of an idea about how much work really goes into such a project.

Random thought ... why not stack the bricks the other way? Rotate 90 degrees and recoil will push the bricks together, rather than form cracks. Maybe, possibly. Or maybe I should shut up, you seem to know what you're doing.

January 2, 2014, 10:38 PM

I have no idea what I'm doing, only that as far as I can tell no one's done this before, despite it being possible for the last 51 years.

Having last used plastic bricks 30 years ago, I'm falling into the same design conventions of almost all commercial sets - build from the bottom. It would be stronger to build from the back, but when I sat down to encapsulate the buffer tube, it was easier to build from the bottom, as I could more easily get studs to line up in the buffer tube stock lug holes. There certainly may be a better way to build it, but I'm going to try more epoxy first, and see where that gets us.

I won't send you a big bucket of bricks, but you would be amazed at how many used bricks you can buy for little money on these sites:

You can download brick CAD software here that will run on a regular Windows PC:

I'm using LDRAW to generate a CAD diagram of Version 5 of the stock, but the bottom's not finished yet.

If you need an upper to practice on, this should work:

January 4, 2014, 07:26 PM
Threw $15 of Loctite Plastic Epoxy in it last night (3xtubes). Bricks swallow a LOT of epoxy. It should be tight for this week's shoot.

Demographics remain the same @ this week's gun show. Kids almost universally love it, women like it, a small percentage of men are interested in it.

January 6, 2014, 01:12 PM
I like the heck out of that!

First thing I thought was "If this guy keeps going and eventually builds his'self an entire rifle out of Legos he's gonna' traumatize anti-gunners the world over, and kids will wail when they can't have Legos anymore because they've been banned from the toy stores everywhere".

January 9, 2014, 04:15 PM
New video:

The epoxied portion holds together just fine; however, around the 35th shot mark the unglued bottom portion shakes loose & falls off. Yet more epoxy indicated; will have to begin buying it in bulk.

January 9, 2014, 10:23 PM
I like it!

Needs a grip and fore-end as well.
Effort Forend is up. (

January 11, 2014, 11:24 PM
OK, I'm interested enough to subscribe - will check out videos at home

July 2, 2014, 09:23 PM
For Dave:

Heat shield isn't installed in the brick lower handguard, and they're not glued.

July 5, 2014, 08:39 PM

Very cool.

Did you try stacking bricks that direction for stock yet?

July 6, 2014, 10:22 AM
Yes, yes I did, after the 2nd shot of a 3" 00 12 ga round sheared the stock in two. Stock is now built in 2 directions, and has eight 10-24 threaded rods reinforcing the butt. That held up to 24 rnds of 12 ga 3" 00 before my shoulder called it a day.

August 6, 2014, 08:53 PM
21 pages of assembly instructions for the Mk8 entry length stock. Enjoy:

August 13, 2014, 09:22 PM
The afternoon's work:

The sloped bricks will be glued into the A2 pistol grip (a standard AR-15 part, cost me $3) w/ my favorite volumetric glue - 2-part epoxy, costing more than the pistol grip to begin with. The lower receiver is an Aero blem - ran me $60 & an FBI background check @ a Texas gun show. The rear butt is near stock Mk8, w/ very slight improvements. Now I just have to connect everything together. Likely the bottom beams will be replaced w/ 2 hole 2 x1 Technic bricks, w/ the ubiquitous 10-24 rod running through the holes.

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