Polymer80’s New 80% .308 Receiver–SHOT Show 2015


So you want to get your hands dirty with some Do-It-Yourself gunsmithing? Try Polymer80. This may be the most efficient way to learn how your AR pattern rifle works. The lowers are classified as 80% complete, which means you don’t have to treat them as firearms. They can be shipped to your house. You don’t record their serial numbers on any 4473, or any other form. It is not yet a firearm.

With a little bit of elbow grease, and the help of a drillpress or milling machine, they can become viable firearms. Cutting them is easy enough. Polymer is much easier on tools than aluminum (which some 80% lowers are made of). After cutting pockets for a few of the internals, the new receivers can be fitted to AR uppers (which are also not considered firearms) to form working rifles.

Ploymer80 began with AR-15 blanks and has since expanded to include polymer .308 lowers. The ones we saw at SHOT Show look good. They come with detailed instructions, a drilling jig to help guide the process, and the black polymer lower blank.

My question about the use of polymer had more to do with the longevity of the material than the cutting process. The crew at Ploymer80 said they’d gotten great results from their polymer. Its elasticity allows it more flex than aluminum, which means it can take the abuse of recoil without developing stress cracks.

We’ll have on in house ASAP, and will chronicle the process. If you want to read up on our 5.56 Polymer80 lower, just get your clicker clicking.

The new .308 lower in the jig.

The new .308 lower in the jig.

The polymer has been formulated for extra strength.

The polymer has been formulated for extra strength.

The lower, ready to go.

The lower, ready to go.

The polymer reacts better, we're told, than some metals. It has more elasticity, and handles recoil energy without cracking.

The polymer reacts better, we’re told, than some metals. It has more elasticity, and handles recoil energy without cracking.

The polymer is lighter than aluminum, too.

The polymer is lighter than aluminum, too.

The 5.56 lowers have been a big hit with the DIY crowd.

The 5.56 lowers have been a big hit with the DIY crowd.

{ 16 comments… add one }
  • Chris Speakman August 2, 2016, 3:51 pm

    Cannot recommend polymer 80 to anyone as they last less than 500 rounds. When the bolt carrier group kicks back it impacts the polymer at the buffer tube connection. Specifically it is the gas key block that eats away at the buffer tube connection. Tried a mil spec buffer spring and same results.
    Additionally, do not trust their milling bit depth guage lines. I built three and the milling bits were all different depths, and the longest one blew thru at trigger. Contacted customer support with pics, got canned reply on checking with their suppliers, and then no reply.
    Cool concept and a fun project, but it is a limited use lower to keep on the shelf as a worse case scenario backup.

  • KARL July 2, 2015, 8:24 pm

    how do I get intouch with you so I can purchase the 80% lower receiver from you .

  • Mark N. February 10, 2015, 2:29 am

    I built one of the 80% lowers from the California company that was shut down by the ATF. (I am pretty sure that the ATF eventually backed down, but that is a different story). I am no gunsmith, I do not have a drill press (which would make milling these things incredibly easy), but I turned out a functioning and reliable firearm, and had a blast doing so. If it breaks, I’ll build another one, just for fun. It is not as pretty as a stripped lower, but do I care? Hardly. Nor do I care that I can’t sell it unless I register it and have a serial number engraved on it, because I don’t plan on selling it. And the upper I put together was made with the parts I chose to build it with.

  • Lonnie February 7, 2015, 11:31 pm

    I have purchased poly 80 ar15. First and second Generation. So far on the rifles no problems on the range. But hopefully on the 3 generation ar15 and new ar10 lower that the jig and diy instructions are finally done with the growing pains. But the lowers Are bad ass.

    • ar fan February 11, 2015, 5:13 am

      Finally something from someone who has experience with a diy poly lower. Thank you youve convinced me to try and make one.

      • Bob October 15, 2015, 6:15 pm

        I have DIY’d a poly and aluminum lower. The poly was very easy and took about 4 hours. The AL took a long time due to doing a bit at a time.
        The poly is a Gen 1 from the company mentioned in the article and has held up to the 500ish rounds put through it. It has done so with main walls being thinner than spec. It has since been demoted to a .22 AR, but I about to order another and mill it better and put it with a 6.8 or 25-45.

  • Gun Enthusiast February 6, 2015, 10:06 am

    I can appreciate the DYI aspect of it and the appearance of gunsmithing. It is just drilling holes through a template which requires no skill, teaches you nothing about gunsmithing but just a way to skirt the law. The downside is people who can’t do paperwork will flock to these. Once the first shooting or killing with one of these receivers happens, it will echo through the anti gun crowd for decades. It will give them excuses to try to ban legal versions of the AR as well.

    We talked to the BATFE at the last gunshow and they are already in the process of trying to eliminate the DYI receivers. If it happens or not we will see. People thought it would never happen to the 10/22 bumpfire stock, they would never question the AR armbrace and so on but look what is happening no wonder this president.

    • Robert February 6, 2015, 12:19 pm

      And which gun company do you work for?

    • Loran Kelley February 6, 2015, 2:52 pm

      The ATF has been saying that for years. They are not anywhere near shutting this down. They tried and failed miserably to do so in CA. In fact they have been pressured by the courts there to get more specific on the laws regarding these and they have. 80%ers aren’t going away anytime soon.

      The ATF’s policy is right here: http://www.atf.gov/content/contact-us/pressroom/receiver-blanks-Q%26As

      Secondly because this industry is absolutely acknowledged by the ATF and they issue letters of determination to companies like mine, it is by no means “skirting the law”. It is an absolutely legal, recognized and legitimate practice for individuals to make their own firearms. It is within the law to do so and it is not a loop hole or getting around anything, its a popular recognized part of the fire arms industry.

      Regarding felons obtaining 80% lowers; they obviously do but even more felons obtain serialed firearms by a MUCH bigger margin, all this proves is that 4473s and gun registration are totally useless.

      And there have been several shootings with 80% guns already and nothing really has come of it.

      • Nathan M February 6, 2015, 9:09 pm

        Well said.
        Didn’t they try to push more legislation after those DIY AK’s were found awhile back? I swear, here in Cali there’s more gun laws every year. The words “ghost gun” need to disappear also.

    • Michael A. Gentis February 6, 2015, 10:23 pm

      Skirt the law? Are you kidding me? You sir, know absolutely NOTHING about the law. You sound like one of those libtards spreading non-truths and believe if you say it enough it will be fact! Your spouting garbage on the wrong site my friend. People on this site know guns for what they are, a tool. And the law definitely says that it is perfectly legal for a law abiding citizen to make his/her own firearm. What it doesn`t say is that you can “skirt” the law.

    • pfc February 7, 2015, 10:34 pm

      I think “gun” enthusiast should find something else to be enthusiastic about, you are oblivious to the whole concept of the right to keep and bear arms. If there is no commerce of a “gun” as defined by law then the government has no power or authority over your right. If I make my own gun and I have no “infirmity” status by law (felon, mental illness, etc) then I have fully expressed my right to own one. Legal limits to technology, particularly arms tech are the hallmark of despotism, when kings outlawed the possession of even small amounts of metal least the peasants make their own arms and assert their sovereignty over themselves. That’s what the Second Amendment is really all about, who is in charge? The whole people or the people who are in/and control the government?

    • Mark S May 10, 2017, 4:25 pm

      “No wonder this president” ?? What a stupid thing to say. Trump is all about supporting the 2nd amendment and has said on many occasions Americans should always have Gun rights and the right to protect themselves WITH GUNS. You must be an ignorant leftist libtard. Bet you never investigate anything but instead watch all the liberally slanted LIES put out by ALL the major netsworks except FOX. IF you want or can handle truth start watching FOX

  • Will Drider February 6, 2015, 9:43 am

    I did a Net search for stress cracks AR10 lower and nothing on metal lowers. Found a lot on poorly manufactured poly from another company. Is stress cracks a real issue on metal lowers? Flex in a lower is a benifit they say. This seems contrary to the basic tenets of gunsmithing.

  • Joe February 6, 2015, 8:02 am

    Once upon a time I laughed at the polymer frame concept. When Glock invaded our shores and took over most Law enforcement agencies in a ten year span I began to waver just a little bit.
    Now I’m really getting interested.
    Where can I log on to a site to look into a purchase of one of these ?

    • Brian Meyette February 6, 2015, 10:10 am

      link is first line of review

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