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80% Arms AR 15 Jig Adventure

I had the opportunity to borrow an 80% Arms AR 15 jig from someone that I know (in fact, I also borrowed the router from another person) leaving me with a fairly cheap build. My only cost being the lower receiver and lower parts kit. This article will walk you through some of the lessons that I learned with this jig and give you a scored review at the end.

80% Arms Jig – The Adventure

Even though this is a fairly simple build to complete, I did find that it is extremely easy to cross-thread screws when putting the jig together. If you follow the directions step by step extremely carefully, you will avoid this problem. If you are paying close attention to our 80% Arms Easy Jig Gen 2 Step by Step AR 15 Lower Completion video, you will see that I show you there are 5 short cap screws that are silver in color.

In the video, when I drill the hole, you will see that there are 4 silver cap screws and 1 black cap screw. When filming, I sometimes have to re-do steps off camera because a picture didn’t turn out. When putting the jig back together I cross threaded a screw. Fortunately, only the screw was damaged and not the jig itself. A quick run to the local hardware store to get a 1/4-20X12″ cap screw allowed me to continue. Of course, it was black instead of silver. 

Later on in the filming of the video, I was not paying attention and accidentally cross threaded the long cap screw into the left side plate. This happened because I didn’t have the top cap screws loose so the side plates could align themselves. I was unlucky in the fact that I could not find a cap screw at the hardware store to replace this one. This forced me to purchase the screw replacement kit from 80% Arms. It is not that the replacement screw kit is expensive (about $5). It is that the shipping is a flat $8.88. When the screws arrived I found that they shipped First Class Mail. For this price, I would have expected it to be USPS Priority or Express Mail. 

If you follow our video carefully, you shouldn’t fall into the cross-threading problem that I discovered when playing with the jig.

80% Arms Jig- Cutting Fluid

Other than paying attention to the screws to prevent cross-threading, I learned a lesson about using cutting fluid. When cutting and drilling, I like to use Oatey dark cutting oil to cool the bits and provide lubrication to elongate the life of the tools. I learned quickly why 80% Arms recommends WD-40, other than it is readily available and probably is in just about everyone’s garage already. The Oatey dark cutting oil worked fine for the drilling process. However, the milling process was a completely different story. The cutting oil tended to capture the chips and let them stick to the router, jig, frame and basically, everything else making cleanup a small nightmare. 

80% Arms Jig- Tools

Although not a specific problem with this particular jig, one thing that annoys me with jigs, in general, is that you need to purchase the “tooling” separately. For the price of these jigs, they can afford to send you the 3 cheap drill bits and their “proprietary” router bits. If you purchase this jig, make sure that you purchase the tooling to get the drill bits and router bit.

As I mentioned above, I borrowed a router for the build. The use of my router would have caused me to have to purchase the large router plate. When you order your jig, make sure that your model of the router you use does not require the large router plate. Fortunately, their website has a router compatibility list that helps you make your decision.

Now that I have covered the basics and lessons learned, let me move on to my impressions about the product. 

80% Arms jig – impressions and ratings

Look and feel – 4.3 out of 5

This is a solid product and you can feel it in its weight. Jig plates are well marked and easy to understand. There are no cheap parts in this kit.

Features – 4.0 out of 5

There are two versions of this jig. The AR15/AR9 version and the multi-platform which allows you to do the AR15, the AR9 and the AR10 (308). The AR15/AR9 jig is not convertible to give you the option to do an AR10 later. If you ever want to do an AR10, you should purchase the multi-platform jig upfront. 

One nice optional purchase available for this jig is the hand drill stabilizers. These allow you to get better accuracy when using a hand drill to drill the hammer, trigger and selector holes. If you don’t have a drill press, this may be the best $30 you can spend to complete your lower. Although I did not get to test these, I like the option so that DIYers can reduce their cost of building their lowers. 

I may just be spoiled by Matrix Precision and their 1911 jigs, but at this price point, I would expect to see hardened bushings in the side plates of a jig to give longevity to the side plates. However, looking at the competition, there is only one other AR jig that offers bushings for longevity and that is Juggernaut Tactical’s Ultimate Jig. 

Ergonomics, reliability and accuracy – 4.0 out of 5

The Jig produces an accurately cut lower with little effort. My build went as planned and no real gotcha’s, as long as, I was paying attention and following the directions. It is important to follow the directions when putting the side plates onto the jig. The natural tendency is to fully install the cap screws for the side plates. Unfortunately, this leads to cross-threading the long screw. You need to make sure that the cap screws are loose then install the long screw. This will keep you from cross-threading the screws.  

This product should have been designed so the left and right side plates are installed parallel to each other every time without having to fiddle with it. 

Affordability – 4.0 out of 5

You need to think ahead about if you are ever going to complete an AR10 lower. If you don’t, you will have to purchase the jig all over again. 

Replacement parts are priced comparatively with their competition. However, shipping for the replacements is a bit expensive unless you are purchasing several parts. Make sure you take advantage of 80% Arms’ flat rate shipping and stock up on parts you may need. 

Even with the lessons that I learned the hard way, I had fun with this build. If you pay attention to the gotcha’s, you should have no problem completing an AR lower with this product.

Building an 80% firearm is definitely more expensive than purchasing one. However,  you will have the satisfaction and pride of completing your AR lower yourself using the 80% arms jig.

Completing an AR lower is definitely the easiest of the 80% rifle builds. You should be able to complete this lower in about 30 minutes. 


This is an unbiased article and I do not have a relationship with 80% Arms. I have not been compensated for this build. In fact, I borrowed this jig from someone that I know. As usual, I do not advocate bypassing (breaking) federal, state or local laws or ordinances. Living in Montana, I have no laws or ordinances that required me to modify this rifle’s features. I may talk about or show you items that may not be legal where you live. If you like the work that we do here at The Rogue Banshee, please consider supporting us for free by clicking on our affiliate links before purchasing gear, parts and tools or donating to us on Patreon.