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  80 percent AR15 LOWER RECEIVER JIG
80 percent AR15 Lower receiver jig

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Our Price: $94.95


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In Stock with Free Shipping: Jig is use to finish your AR15 80 percent Lower Receiver. Includes both Milling plates, Drill Press Plate and needed drill bits.

Part’s Included:

1 –Steel Milling Plate 1
1 – Steel Milling Plate 2
1 – Steel Drill Press Plate
1 – 5/32 Drill Bit

4 – 10-24 x 1/2 Bolts
1 – 1/4 – 20 x 1 3/4 Bolt
1 – 1/4 – 20 x1 1/2 Bolt
1 - 31/64" Drill Bit
1 – 3/8″ Drill Bit
1 – 7/16″ Drill Bit

1 - 1/8" Drill Bit

Customer is responsible for compliance with local state and federal regulations regarding any products sold on our website.

You Must Legally be allowed to possess a firearm

If you live in CA, you need to be careful to follow the laws related to the Assault Weapons Ban. In general, if you build AR-15 style rifle with a pistol grip, you will need a "bullet button". There are configurations that do not require a bullet button. For more info on following CA Laws, has a very helpful flowchart:

Tips: I like to drill the trigger pin and safety holes after I finish drilling or milling the magazine well and safety pocket. This leaves very little material to drill though to deflect the drill bit off center. If you 80 percent lower does not have the rear take down pin already machined. Just extend the safety pocket (but only 9/16” deep) out using the 7/16” drill bit until you are 1/8” from the buffer retaining pin hole and stop. Instructions for this operation included.

For receivers that are not anodized, one product that you can use is Brownells Aluma-Hyde II for your finish. We found this product to be surprisingly tough and easy to use. The only drawback is the curing time, 14 days. Brownells website has instruction videos on using Aluma-Hyde and other like Cerakote.

From Shot Gun News

An 80 percent receiver is simply one that is not finished enough to be considered a firearm by the ATF. To the Feds it is a chunk of aluminum and can be purchased online without an FFL. You can finish it for your personal use as long as you may legally own a firearm but you can’t sell it unless you’re a licensed manufacturer.

Finishing a lower requires a milling machine or drill press, a fixture if you choose the drill press method, some drills and end mills and very basic machine skills.

I think most people tackle a project like this because they like making their own stuff. It’s the sense of accomplishment more than anything else. It’s going one step further than simply assembling a rifle kit from finished parts..

Finishing one of these receivers on my Grizzly Mill/Drill was not a big chore. AR-15 lower receiver blueprints are readily available online, and my main concern was calculating the dimensions from the drawings correctly. The holes for the selector (3/8″) and trigger and hammer pins (5/32″) were drilled first and they must be precisely positioned for proper function of the fire control group.

Once the holes were done, it was simply a matter of milling out the receiver pocket with a long 7/16″ end mill and finally cutting the slot for the trigger with a long 5/16″ end mill. Inside dimensions of the pocket are not super critical, and a few thousandths error probably won’t be noticed.

One error I made was not cutting the rear channel deep enough into the buffer tube threads, and when I checked the fit of an upper receiver the takedown pin wouldn’t quite line up. I milled in a little more clearance and the problem was solved. I would rate finishing one of these receivers on a mill as well within the capabilities of any hobbyist with basic machine skills.

Finishing a lower on a drill press is also possible. You will need a fixture that consists of plates that clamp around the receiver to guide the drills and end mills. With the side plates drilled for correct positioning of the trigger pin, hammer pin and selector holes.

Three separate top plates are included for different steps of the machining process and a tool kit is available with the fixture which includes the drills and end mills you will need. Most of the aluminum is removed by drilling overlapping holes with progressively larger drills.

It is important to be able to set the depth on your drill press accurately with a dial caliper.

Test-fit an upper receiver to the lower when you think it is finished to make sure the takedown pin holes line up and the upper slides into position easily. Also, test fit a standard mil-spec hammer, trigger and selector to check function of the fire control group.

This article is simply a quick overview of how an 80 percent lower is finished. For a more detailed discussion of the process including finishing a receiver on a drill press look for my full-length article in an upcoming issue of the Guns & Ammo Book Of The AR-15.

Lower Receiver Jig Instructions

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AR 15 80 percent Lower Receivers