I couldn't find a significantly lighter upper, so I decided to design and print my own...




Here it is on a NFA Polymer lower...



Add 2 pounds for a lightweight barrel assembly, hand guards, FA, and dust cover and you have a sub-5 pound AR. Now who here wants to test fire it!

ETA: So no one is confused... I'm not actually going to fire it, just did it for a fun little project. I am however going to use that lower with a real flat top upper and LW barrel at some point soon.

pretty sick. How do you have access to a 3d printer? work related?

We have a couple here at school but the high end ones are reserved for special projects and stuff. Ive printed a few small pieces just for fun on our budget built printer. Its neat stuff.

You should print out a BCG, CH, and gas block too.

I'd shoot it.

Would be awesome in my 22lr

Nice job!

I'd buy it if it was strong enough to handle 5.56/6.8 Recoil...

This, I'd give it a try at least!  

~Augee

haha nice rapid prototyper...we have one of those where I work as well. Don't know if that material will be able to hold up but please let me know if you try it ha. I may be making my own if you still have the file and would be kind enough to forward it

How much do you think you would save if you shaved off the f/a, brunton bump and most of the rail? Sort of like a 604 or prototype upper with just enough rail to mount a rear sight of some kind.

Just curious is all.

That is pretty sweet

I guess I never though of 22lr, really all the forces go strait to the recoil spring on the carrier and then to the buffer tube part of the lower, my only worry would be how well the threads mate to the barrel nut. I honestly might try that... depending on how square the barrel is to the receiver when I mount it.


I printed it at school for a project on an older Dimension printer, sometime soon they are getting the newest version with multi-color and water soluble support material... but I'll pry graduate before then. Luckily I've been working on a reprap so I can keep playing with making parts, its got a ways to go though. Charging handle wouldn't hold up to one charge, the walls would be too thin for the ABS plastic. I'm planning on making a bolt carrier, as well as lower receiver.



Download the one from CNCGuns.com as I'm sure its more accurate than mine.


Milspec Upper has 4.5 cubic inches volume. Chopping off the FA, brass deflector, and half the rail brings it down to about 3.9 cubic inches, so 86% the material of a regular one. Just take your uppers weight times .86 and that's your answer.

NICE !