80% Arms Update Complete Rifle (image courtesy JWT for thetruthaboutguns.com)
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Last month I completed three different AR platform lower receivers using the 80% Arms Easy Jig Gen 3 Multi-Platform 80% Lower Jig.

The Easy Jig is a great product, and provided much better results than I would have expected. It was also very simple to use, with easy to follow instructions and a process you’d have to work at to get wrong.

I had all the parts available to create and test the AR-15 platform, which is still running like a champ. But it took me a bit to find the parts necessary to complete the lower receiver and build an upper receiver for the AR10.

That ended up being a great opportunity. A long time friend of mine who owns Underground Tactical let me peruse the trash bin at the shop. Over the years, people have asked for their guns to be upgraded with better parts. Sometimes they want their old parts back, but usually not.

Image courtesy JWT for thetruthaboutguns.com

Well, one man’s trash is another man’s treasure. With just a few important exceptions, I built the entire AR10 using the recently completed 80% Arms 80% AR10 lower and leftover parts from other people’s guns.

First, it could have been a whole lot easier. Unlike the AR-15, there is no MIL-STD or “milspec” for the AR10 platform. They are built a lot of different ways, with several key component variations. Little things, like detents vs. screws in the lower small parts kit differ from one lower receiver to the next.

If I had been more patient, I would have simply ordered one of the lower small parts kits from 80% Arms. That would have given me everything I needed for this specific lower receiver. Instead of waiting, I chose to raccoon through small parts bins until I found each part I needed to fit the receiver.

In case you are wondering, it’s a DPMS pattern.

The receiver itself finished out just as well and just as fast as the AR-15. Just like the AR-15 version, the trigger pocket is a little wide. In this case, about 20 thousandths of an inch. That means that the trigger is going to wobble a wee bit inside the pocket until the spring arms are set into the little grooves on the pins.

Image courtesy JWT for thetruthaboutguns.com

Just to make sure it would fit, I pulled a CMC trigger out of the packing and installed it. It worked just fine. But in going with my “do it fast and do it cheap” goal for this build, I chose a binned mil-spec trigger. After a bit of polishing to smooth up the otherwise gritty trigger, it fit in just fine.

Image courtesy JWT for thetruthaboutguns.com

I found one small issue with the lower receiver during the assembly. The rear takedown detent pin pocket had not been completely drilled through. This pocket comes pre-drilled from 80% Arms, but it ends about 98% of the way down. That means the detent barely pokes down, and doesn’t fully retain the pin from walking back and forth once installed. A quick pass with a narrow bit and a hand drill fixed the problem.

With the lower receiver finished using literally thrown away and leftover parts, it was on to the upper.

Two parts that didn’t come from the trash were the 22″ 6.5 Creedmoor barrel and BCG.  These were both Underground Tactical parts sitting on the shelf and are of the highest quality on the market. I went with an unfinished upper receiver from a model that Underground Tactical hadn’t made in years.

Image courtesy JWT for thetruthaboutguns.com

The whole process, including milling the receiver, took about two hours. The total cost, not including the jig, but including the cost of the 80% lower, would have been just a hair under $700, if I had purchased all of it online instead of finding most of it laying around the shop.

Once complete, the upper pinned right on the lower and it was time for finishing.

Which, of course, was backyard rattlecan.

Image courtesy JWT for thetruthaboutguns.com

Using Hornady’s 6.5 Creedmoor 140gr ELD Match ammunition, the gun shot just barely under 1 MOA five-round groups at 100 yards. With the handloads I make for a Ruger M77 Hawkeye Predator, it shoots just barely over 1 MOA five-round groups at 100 yards.

I initially poured some of the leftover vegetable oil from milling the receiver into the gun for lubricant, but after about 100 rounds it started to gum up a bit. I cleaned it all out with KANO Sili-Kroil and then added some CLP to the bore and BCG.

I’ve got about 300 rounds through the gun now. It’s running great and has taken an honored place in the pickup, replacing a hacked-up Mosin. Quite the upgrade.

I’m once again impressed with the product from 80% Arms, and I’m looking forward to building out the AR9, this one with a pretty cool Brownells complete upper. Watch this space.

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  1. Image Five shows why this should be illegal.

    Clearly, that rifle is floating in midair. That means it’s a… ghost gun!

    Now, go destroy that evil creation before it flies off and shoots a bunch of people on it’s own, it can fire like a whole 30 caliber clip per second FFS!

    Seriously though, well one.

  2. Shit, Jaydub… you’ve been busy lately. Thanks for the articles, keep them coming. With ammo and gun trade markets the way they have been, “vicariously “has been the only kind of living I’ve been doing lately !!

    • The ammo market does indeed suck, but it’s got me back into the dry fire practice where I should have been at the whole time. It’s also got me focusing more on long range in alternative positions.
      Starting in April I have some really great hunts picking up, and man, I’m looking forward to that.
      South Africa plains game leads it off.

  3. I would wager that if a person purchases something with a credit or debit card from someplace called 80% Arms over the Internet, Big Brother makes a note of it.

    • I didn’t think of this before, but Google and Facebook probably know where you shop too if you have accepted their terms of service.

      If you’re a law abiding citizen with nothing to hide who wants to build one of these things out, good for you. My thinking is that if the state deems you worthy of weapon possession, you should be able to possess what you like, so long as the consequences of an accidental discharge are fairly minimal (which is why nobody gets nukes).

      But if the state doesn’t want you to build one of these things out, you had better think twice. Just because it’s 80% doesn’t mean you’re not going to get caught.

      • The wife and I just started doing ancestry. They had the address of my old double plus top secret mail drop from back in the 1980s plainly associated with my name.

        Relax. They already know everything.

        • Ah yes, I remember those days well. Management ordered me to to liquidate both you and your double, but I convinced them to let you live so we could track your movements and keep tabs on your associates. We have a file on you that is three inches thick.

          But Seriously Folks, the government doesn’t know everything. But I’ll bet it knows a heck of a lot about people who visit 80% Arms on the Wubs.

  4. Nice work. Been there done that. But I have put my LR308 builds in storage rank. They have been replaced by 20″ 6mm ARC builds. The weight difference is impressive. You give up a little lethality beyond 1,000 yards but… The 80% arms easy jig gen 3 multi platform is expensive but it works well and has the necessary utility to amortize that investment. You can even share the jig with friends but they have to buy there own cutters. Makes it affordable. Today’s wait list is 3 months.

  5. Nice frankengun. I always enjoy them. It’s just kinda cool when you get to create something and then it works

    • Thanks for the chuckle. I had 3 thoughts in quick succession. First was a memory of a pair of ‘coons climbing into a dumpster at Fort De Soto Park many years ago. Brother and I watched them slip in through the crack between the lids, and we snuck up on it and started whacking on those lids with a couple sticks. Never saw a ‘coon move that fast before, or since. Ungainly, long legged swamp ‘coons quite unlike their northern cousins. Second was a picture of a cheesy-grin JWT standing up in some seedy back alley dumpster, triumphantly holding a small spring between his thumb and forefinger. Third was, how far am I willing to go to collect the final parts for a build I’m working on, in this age of scarcity. Ok, a fourth. Whatever it takes to get the ‘coon.

      Congrats on a completed project that looks cool and shoots well.


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