80% Arms Billet Aluminum Lower Build-No Milling Machine Needed ? GunsAmerica Digest80% Arms
: 80% Arms - AR15 80% Lower Receiver | Billet 80 Percent Lower | Lower Jig
“With certain exceptions, a firearm may be made by a non-licensee provided it is not for sale and the maker is not prohibited from possessing firearms.” ATF: [18 U.S.C. 922(o) and (r), 26 U.S.C. 5822, 27 CFR 478.39, 479.62 and 479.105]
You heard it from the horse’s mouth! As long as you can posses a firearm, you can legally create your own firearm! But how does anyone short of a machinist create a firearm?80% Arms has made it simple.
Hidden behind enemy lines in the Peoples Republic of Californiaistan, 80% Arms is a company whose mission is to help you help yourself create your own firearms.
80% has brought to market no compromise 80% lowers in both AR15 and AR10 patterns. An 80% lower is just what it sounds like. It isn’t 100% complete. The lower is 80% of the way there, but requires some finishing to make it an actual firearm. You’ll need to remove material for the trigger group and drill some holes. Without these additional steps, it might as well be a paperweight. But because it isn’t technically a firearm at the 80% completion point, it can be shipped directly to you without the hassle of an FFL and form 4473.
You will need some guidance, a few tools, a few jigs, and billet to complete a firearm.Features of the Lowers
- Full mil-spec part compatibility ensures maximum rifle customization.
- Machined from 6061-T6 billet aluminum for superior strength, 7075-T6 optional.
- Broached, flared mag well aids with faster, easier magazine reloads.
- Integral trigger guard enables winter use with gloves.
- Easy bolt catch installation with a regular punch eliminates need for special tool.
- Lifetime warranty against manufacturing defects.
- Three finishes available: raw aluminum, bead blasted matte aluminum, and mil-spec type III hard anodized in black, flat dark earth (FDE), and pink.
Besides the lowers, they also have a universal jig that makes the completion of your lower receiver as easy as possible. The jigs are designed to be used with hand tools and a simple vise. A novice can easily complete a lower receiver in a matter of a few hours. Available as replacement parts or as a whole kit, it gives you an easy to use jig that is designed to be universal for all AR15 lowers.
The kit doesn’t include the drill bits and mills but they are available from 80% Arms for an added cost of about $45. If your going to complete one of these lowers your going to want to purchase a few tools and miscellaneous things to make sure its smooth sailing.
Cordless drills may not cut it. Go for a larger drill, or a drill press.Other tools needed
Nice to have
- Trim Router
- Corded drill
- Shop glasses
- Cutting fluid
- Drill press
- X Y vise
- Air compressor with nozzle to blow out chips
Milling out the lower doesn’t have to be done on a milling machine. A router will work.Cost of lower and parts necessary for build
How to mill out the lower
- $99.99- 6061-T6 Anodized Billet 80% Lower
- $149.99- AR-15 Easy Jig
- $44.99– Easy Jig Tool Kit
First things first. Lay out your parts and tools and make sure you have everything you need for the job. Assuming you’ve got all the right parts and tools, it’s time to assemble the jig around your lower. Installing the 4 cross bolts in the jig firmly locks the lower into place and keeps it centered and free of movement.
Add the appropriate top section of the jig. You can now prepare for drilling the front trigger pocket. Lock the jig in the vise. You now use the supplied drill bits and stop collar to drill the depths of the front pocket. Though it is possible with a hand drill, I’d say if you have access to a drill press, use it. It’s good to use lots of cutting fluid and to take small breaks fairly often to clear the chips of aluminum from the jig.
Setting the depth on the bits is crucial. Don’t drill too much material. Removing it is much easier than putting it back.
The next step in the process is to drill the rear trigger pocket. Remove the top rear bolt in the jig. You now set the proper depth on the drill bit and go to work as you did on the front pocket.
The next step in finishing your lower is milling out the remainder of the aluminum with a router. I used a DeWalt Trim router and found it to be perfectly powered and sized for the job.
It’s important to do this part very gradually to achieve clean and even lines inside the lower. Taking half steps at a time you should start inside one of the drilled holes and move toward the center of the jig, slowly connecting the dots. Once you get the mill bit below the walls of the jig, you can move toward the sides of the lower. I made around 12 passes to get the pocket milled out to perfection (or as perfect as I could get it). Next I moved to the rear of the pocket taking the same caution to make smooth passes (moving from hole to hole then moving outward to the sides of the jig).
After the pocket is cleanly milled out, drill out the trigger hole. Using the trigger hole template, make a square cut and then switch to a mill bit and expand the hole to size.
Drilling holes for the controls requires a bit more control. The angle of the holes is important, so I opted for the control offered by a drill press.
Once the pocket is complete, turn the jig on its side and drill the selector hole as well as the trigger pin holes. Using the supplied bits, make sure your holes are straight and square to the receiver. I found it easier to flip the jig over and do one side at a time. After the holes are drilled, disassemble the jig and clean off your freshly finished lower.
After removing the remainder of the aluminum chips and excess cutting fluid, I would say the lower came out pretty much perfect. Apart from a few cosmetic blemishes (due to negligence on my side) the lower came out better than I had expected.A few tips
Go slow and make sure to check your depths frequently, I had the drill stop slip a few times. It is better to make twice as many passes with the router than to make deep rough passes. Gloves would be a great investment because tiny slivers of aluminum will slide under your skin very easily and may cause annoying discomfort. Deburr the selector holes to ensure smooth operation. Though not necessary, I will eventually recoat the entire lower with Cerakote.
The process makes a mess. Go slow. That will allow you to clean up frequently and judge your progress.
It really isn’t all that complicated. There are some out there who think you can’t make a functional aluminum lower without a milling machine. Even though I did use a drill press for a few cuts, I didn’t have to. And I got a fully functional lower without a milling machine.
80% Arms has something unique here. They have a quality system that makes building a lower receiver so easy that you can do it from home with minimal tools. Yes, you can go out and buy a completed lower for less than it would cost to complete one from an 80% billet, but there’s more to it than that. And the jig and tool kits are reusable and all the parts of each can be replaced, making this an investment you can depend on for years to come.The Real Question
We’ve written about the 80% lowers before. They can be a bit of an enigma to those who don’t know guns. This lower isn’t serialized. That scares some people. They want to call it a ghost gun, or some equally terrifying name. People who have an irrational fear have a crazy irrational fear of these things. They think thugs are going to line up with their milling machines and start churning out machine guns and no one is ever going to know.
The process is nearing completion. In a couple of short hours (and I was taking my time) I had a fully functional lower.
The reality is much less terrifying. Because it isn’t serialized, and doesn’t have to be serialized if you follow the basic rules that govern who can make guns at home and what can be done with those guns, this has become a personal liberty issue. You can build a gun, and you don’t have to tell anyone. And if the result is as solid and functional as any other lower you might buy–why wouldn’t you? Unless you are one of those types that likes bragging to Uncle Sam about all of you personal business.
But there’s more to it than that. This is about getting your hands dirty. You can go buy a gun or you can build one. Which do you think you will have a stronger affinity for? Which one will bring you more personal pride? And this way, if something does go wrong with the lower, you’ll know a hell of a lot more about how to fix it. It will be yours. There’s something about the process that I find personally gratifying.
Milling out pieces that are exposed on the outside should be done with extra care, just to make them neat.
The jig has a plate to help support the router.
When set up in a vise, with the jig, routing is very easy.
The jigs are crucial and help with stock removal in incremental steps.
A drill press with its own vice makes the whole job even easier.
The milling inside will almost surely show tool marks, but that won’t change how it functions.
The router zips through aluminum more slowly than wood, but it still works.
The drill holes make milling much more efficient.
80% Arms’ jigs are ideal, and can be used for multiple builds.
The whole build takes very little time. The most time consuming part is the process of discovery. Assembling jigs and pacing the cutting both have small learning curves that quickly disappear.
Getting the appropriate bits is easy through 80% Arms, or you can find them yourself.
These bolts hold together the jigs and keep the work from shifting.