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Preview – Self-Reliance 80-Percent AR-15 Lowers

Find an 80-Percent Lower You Fancy So You Can Build Your Very Own AR

In his famous essay Self-Reliance from the 1800s, American philosopher Ralph Waldo Emerson argues strenuously for individualism, for avoiding conformity, and for all to “trust thyself.” The strength of the individual is a core tenet of our great country, and no less than the Bill of Rights explicitly guarantees personal freedoms for all Americans — including, of course, the right to bear arms.

What better way to practice self-reliance than by building your very own firearm with your own two hands? Articles elsewhere in this issue cover the legalities and step-by-step details of manufacturing your own firearm. This buyer’s guide outlines a selection of so-called 80-percent lowers from which you can build your rendition of the most American of firearms, an AR-15 pattern rifle. Please note that there are many 80-percent lowers available on the market; we are just showing a representative sample in this guide.

Some things to keep in mind:
Billet versus forged: 80-percent lowers are available in both forged and billet (or more accurately, machined from aluminum billet) variants. Last issue, we covered billet upper/lower sets, and the same considerations apply here. Forged lowers will be stronger, ounce for ounce, than their billet counterparts — but both will function perfectly well. Forged lowers more or less all look the same, while billet lowers can be machined to incorporate additional features and aesthetic concerns. Billet lowers also command a price premium.

Material: Forged lowers are made from 7075 aluminum, but you may often have a choice between 6061 and 7075 for billet lowers. How to choose? 7075 is stronger, but more expensive. 6061 can be easier to work on for your average garage tinkerer and, when machined from billet, is more corrosion resistant than 7075 (forgings can be a different matter, hence issues that you may have read about during the early days of the AR-15 platform). Some may prefer to pay a little extra to get the strongest material, but don’t feel bad about going with 6061. Both will get the job done just fine.

Features: Billet lowers may have various additional features, such as integral trigger guards, flared magazine wells, and pins with screws to replace those annoying roll pins. You can also shop around to find one that suits the look you want.

80-percent versus 95-percent: All of these partially formed pieces of aluminum have been determined by the ATF not to be firearms. Most lowers require you to hog out the entire fire-control pocket and drill holes for the trigger bow, safety selector, hammer pin, and trigger pin. Some (including the American Spirit Arms forged, which coined the phrase “95-percent lower” for its offering, Ares billet, and Colfax forged) have additionally started the fire-control pocket for you at the rear of the lower.

Finish: Those who like to “go big or go home” and do things by the book should probably choose a raw lower, complete the machining and any engravings, surface finish to preference (i.e. bead-blast), and anodize the finished product. While more expensive, this will ensure the entire lower (in particular, the pin holes) is hard-coat anodized. Alternately, many a home builder has started with an anodized 80-percent lower and either left the internal machined surfaces and pin holes in the raw, or hit them with something simpler and more economical like Cerakote. But if intended for hard use and high round counts, our preference would be to start with a raw receiver and then type III hard-coat anodize it afterwards.

Preview   Self Reliance 80 Percent AR 15 Lowers photo

American Spirit Arms
American Spirit Arms offers a traditional forged receiver with a nice tumbled finish. They were one of the first to push to machine as much as they could while still receiving a favorable determination from the ATF. ASA calls it a 95-percent lower — compared to many other 80-percent lowers, the fire-control pocket has been started with the upper receiver rear lug pocket already machined. The magazine well is EDM wire cut and moderately beveled.

Model: ASA M4 AR-15 95-Percent Lower Receiver
Material: 7075 (forged)
Finish: Raw (tumbled)
MSRP: $150 ($120 on sale)
URL: www.americanspiritarms.com

Preview   Self Reliance 80 Percent AR 15 Lowers photo

Billet Rifle Systems
Billet Rifle Systems makes 80-percent lowers in 6061 and 7075, available raw or black anodized. The lower has an angular look and features an integral trigger guard, flared magwell, threaded rear takedown pin detent hole, and a pin and set screw for the bolt catch. The magwell is machined. The lowers also have engraved pictograms for the selector markings on both sides.

Model: Independence
Material: 6061 or 7075
Finish: Raw (steel ball burnished) or black anodized
MSRP: $129 (raw 6061) $159 (raw 7075) $174 (anodized 7075)

The Jig Set from Billet Rifle Systems is very affordable and comes with two side plates and a single top plate that screws in and flips around to accomplish each operation. The jig fully encloses the integral trigger guard. The side plates are not as thick as some of the other jigs, but they get the job done (see it used in the DIY on page 40). Tooling is optional and includes a 3⁄8-inch end mill, 5⁄16-inch end mill, 5⁄32-inch drill bit, and 3⁄8-inch drill bit.

Model: 80-Percent Jig Set
Finish: Raw
MSRP: $72 (jig) $64 (tooling)
URL: www.billet80.com

Preview   Self Reliance 80 Percent AR 15 Lowers photo

Tactical Machining
Tactical Machining sticks to the basics with a traditional forged 80-percent lower — there’s nothing wrong with that, and it’s also the cheapest in this guide to boot. You can select between raw and black anodized. The magwell features additional beveling.

Model: 80-Percent AR-15 Lower Receiver
Material: 7075 (forged)
Finish: Raw (deburred and tumbled) or black anodized
MSRP: $78 (raw) $88 (anodized)

Tactical Machining’s jig features side plates with steel drill bushings for the hammer pin, trigger pin, and safety selector hole. It has three top plates for the additional operations. The side plates are a little too short to enclose the integral trigger guards on billet lowers.

Model: 80-Percent AR-15 Jig Gen 2
Finish: Anodized
MSRP: $90
URL: www.tacticalmachining.com

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