80% AR15 Lowers

We are manufacturers of ubergrade AR-15 Lower Receivers.
Ensuring freedom from tyranny, oppression and subjectification.

Build it Yourself

Posted on 21 Jan 2014 in Build | Comments Off

Now What? How do I finish this thing?

You went for it, you are protecting your investment and your freedom. You have your Ownership Number, its your property on its way to your home, or other shipping address. Now what? Do you know the next step you are planning?  Not only is is simple to say ” I am going to make my own gun”.  There has never been a time like this, where the information and support is so readily at your fingertips.  The Home Build AR15 movement has gained steady momentum since 1999-2000.  Resources and machining aids are plentiful, all you need to do is look and read.

What needs to be done

Just take away everything that is not a AR15!  As far as the ATF is concerned a gun does not become a gun until it becomes a gun!  A 80% lower receiver is not a gun.  If it is not a gun it is a piece of metal that is no different than a paperweight or novelty.  Your task will be to use cutting tools to accurately remove all the metal that stands between your paperweight and its birth as a AR15.  It is not as hard as some people think.  Here is the areas highlighted in green that we are being addressed.  Everything else is done for you.

Advanced Rifles AR15 Fire Control Pocket

The green area indicates the material you need to remove in order to complete your lower receiver.


Most of the blue prints out there go back to D.Snider’s excellent drawing of January 2000. Here is one of the first full sets of plans that came out.  The set of plans that we have strips out all the measurements you don’t need for a 80% build.  We have done the work for you to be able to focus on what is important.

AR15 80 Percent Build Diagrams Drawings Measurement

Simplified measurement guides, click to open up the full size, high resolution version. Special thanks to Slate!



What is most important to know is that there is support community of skilled people that have proven willing to help.

Home Gunsmith Community which is a hangout for folks who have done this forever.
AR15 Build It Yourself Archive


A jig can help you know where to remove metal for the Fire Control Group and locating pin holes to making machining easier.  There are several jigs available, even used.  Check the Want To Sell sections of many gun discussion boards and you will find one quickly.

Justin from CNCGunsmithing has been a great contributor over the years in developing open source build resources and a place to buy hard tooling like jigs and cutting tools. There is also a nice tutorial he published and last updated in 2008.

AR15 3D Printed JIG

First Generation of a very low cost milling guide made of 3D printed plastic that you can print at home for free or purchase online. It has integrated depth and width guides for to know if your cuts are correct.


Our advancedrifles.com 3D Printing Jig (open source link will go here with tutorial to follow) Basically you can have it printed in plastic and use it can locate the Fire Control pocket for you to scribe border and machine to the line as well as locate your pin holes.

It doesn’t matter if you are starting on the cheap with minimal tools or have a bunch of money invested in machinery already.  Completing a 80% build is not hard especially with all the help out there.

No mater what method you choose, Welcome to the movement, there has been a ton of effort and talent invested in this community.  We are very happy to support the guys who have contributed, and are making contributions now.


Going Without a Jig

While it seems scary to build your lower without a jig, it is entirely possible to do so without a jig if you have access to a mini-mill or a Bridgeport. Jigs are mainly for folks that only have a drill-press or are perfectionist. We constantly have to remind folks that the fire control pocket does not need to be absolutely perfect. Once assembled, no one will see your little mistakes. The trigger itself can accept a certain amount of slop which can be fixed with spacers, worse case you can drop in a self contained modular trigger group like the one offered by CMC.

Advanced Rifles AR15 80 Percent Fire Control Pocket Milling

Milling out the Advanced Rifles AR15 80 Percent Fire Control Pocket without a jig. All you need is three pieces of flat stock. One on each side to protect the lower from the vise. The last square stock that goes across the trigger guard slot that levels out the lower on the mill. From there you follow your scribe lines or use a Digital Readout (DRO) mill to keep your cuts in line.


Most machine shops are willing to rent you their equipment and provide you basic training. Even in the most expensive cities we have seen a build session going for $50 on Craigslist. What’s included is use of the machine and cutters along with basic training and practice on bar stock. After all, schools used to teach Junior High School students how to use a milling machine, if a child can master a milling machine, an adult will be able to do it so much better.

Here is Emily (Gunners Girl) doing her first 80% rifle lower. Prior to this build, she had never touched a milling machine. In about 30 minutes of instruction and a couple practice cuts, she was a professional. You don’t need to have a TV show to be a gunsmith.

Emily Gunner's Girl AR15 80% Build

Emily building her very first 80% lower. While she grew up with a father that is a well known gunsmith, she never actually built a rifle, especially an 80% rifle. She wants a custom pink rifle that she can afford and build over time, instead of spending thousands of dollars for a bone stock rifle that she will need to tear down.


Big Picture

For detailed tutorials for assembling your AR15 rifle go here to the AR15.com community dedicated to assembly.  You will get a idea of the big picture of what is needed to complete your AR15.

The parts that go into completing your AR15 can be found in many good suppliers on the internet. For around $800 you can complete your custom AR-15, of course you can spend as much as you want and at the end of the day, it is your custom rifle, built by you.

For Starters: