Polymer 80 Pistol Part 2: The Quest for Reliability

Our Counterfeit Combat Tupperware

PART 1 Frankengun Rising: A Gucci Polymer 80 Built by Clay

A week or so back, we slapped together the ultimate Gucci Polymer 80 hand cannon. It was a veritable who’s who of L33T ( that is leet, short for elite, for anyone older than 35) parts, the Glock knockoff we wish we could buy from the factory. It was, in short, magnificent. Looking. Magnificent looking is the operative phrase here because it functioned about as well as a Chinese Stealth Fighter. Which was hugely disappointing, because we want a gun, not a decoration. A gun that doesn’t go bang every time might as well be a poorly designed club, and we at Guns America Digest do not endorse that option.

Magnificent Dawson Sights

This was a let down on so many levels, it actually hurts my heart. Because I personally believe, now more than ever, we should all be able to make our own guns with simple hand tools that are never ever listed on a form 4473. Far from being a conspiracy to sell more factory guns, this is a personal belief need to have. I wanted this to work so bad I could taste it. So we opted to cowboy up and try again.

Gucci RMR cut Brownells Slide

Now as I have stated in the past, I am not a gunsmith. Not even close. You should not even consider letting me near your NightHawk/Turnbull with a screwdriver, and probably not with just white gloves. But I am a Glock Mechanic, forged in the fire of necessity. I not only have a Glock Armorers certificate, but I ran Glock exclusively for all my years on the competition circuit and most of my years in combat. I have seen and corrected things most Glock owners will never encounter in their wildest dreams.

Pin array on P80 Frame

The most stunning mechanical truth about a Glock, to me, isn’t that things don’t break. It’s how well that a Glock will run, even with broken parts.  I had a Gen 2 17 once, that kept hitting to the left one day. No matter how far I drifted the sights, up to have the sight hanging off the dovetail, it was shooting a tight group left of the target. Because the slide was cracked. All the way in half, right at the ejection port. It ran several hundred rounds that way before I noticed, and no telling how far it would have gone. ( Glock warrantied it, despite the gun being 20+ years of hard use old.) I had to order a new locking block for one of my teammates, because his broke, which raised a lot of eyebrows. But it kept working till the new one arrived. The guns are hard as nails.

Author encountering stove pipe malfunction. again.

Which brings us to diagnosing our Polymer 80 build. There is just not that much to go wrong, so I had faith I could fix it. The primary problem we are having now with some break-in is one of two malfunctions, a stovepipe or an inline stovepipe. Which are very nearly the same thing. And typically in a Glock, that is one of two reasons.

Threaded Glock factory to the rescue?

The first possibility is a worn-out magazine. The magazine in a Glock is actually part of the ejection cycle. If you don’t believe me, you can see this for yourself next time you go to the range. Put a round in the chamber, and remove the magazine. Hold your hand under the mag well, like an old school cup and saucer grip. When you fire, the hot brass will fall out in your hand. 100% of the time, at least in 9mm caliber.

Trigger pin, still in working order

Which leads us to the diagnosis problem. I was using all factory magazines, 3 of which are new, without extensions. And while we do see the malfunctions start with extended magazines in race guns, never with standard capacity mags. Extended mags require a spring swap every 6 months depending on use, but not once have I seen a Glock factory mag that is worn out. Which is also true for several other factory brand pistol magazines, but my longest personal experience is with Glock. I have “pre-ban” 1993 magazines, on their original guts, that still cycle every thing I own.

Locking block pin, showing abnormal wear

The next possibility that will cause a Glock to start the stovepipe malfunction is a worn out number one pin. Also known as the trigger pin, this is the big one below the pin that retains your locking block. These pins are usually good for about 20,000 rounds. Also, your Glock will generally run and quit well, even with only half the pin still in the gun. But, for reasons unknown, you will start to get stove pipes whenever the pin is close to breaking. An easy way to tell is to pop the pin out and lay it on a flat surface. If it is U shaped or bowed in the middle, it is about to go. Slapping a new one in is a 100% fix, for the price of about $2.

Locking block, also a bit rough for 400 rounds

Which is also a big problem with our Polymer 80 build. There is zero chance we have worn that pin out in 200 rounds. But….. we did drill the hole that pin resides in. And there is absolutely nothing we can do for that. Cringe O’meter pegged, we have to move onto another possibility.

Frame showing wear also, locking block pin hole

Last, and least likely, is the barrel. For two reasons. First of all, what is the number one consumer demand in an aftermarket Glock barrel? Everybody, it seems demands the aftermarket create a match grade barrel. They want a bump inaccuracy, which means tighter tolerances because they want the $600 Combat Tupperware to also be a 1 inch at 50 yards gun. Which in my opinion also defies logic. You bought a Glock so that mud, sand, and no oil since Moses was the original owner, the gun always goes bang. There is a bit of, shall we say, slop in the Glock design. But, like an AK47, that is also what makes it so stupidly reliable. The minute you start messing with that equation, you start reducing the Glock factory’s legendary reliability. I do a lot of things to my race guns. Aside from sights, I do zero things to my home defense Glocks.

The second issue that a barrel could potentially have is being at the end of a tolerance stack. A tolerance stack would mean, in manufacturing, that we have a whole lot of interacting parts that are all at either the high or low side of the acceptable tolerance. No parts, anywhere, are made to exactly 100% the right size. It might be thousands or ten thousandths, but a parts maker always has a tiny bit of plus or minus. Where this can bite you in the ass is the off chance, but possible, everything is in the plus category, and stacked together stops working. All those parts individually might be fine in other guns. But together, not so much. Add to this one other simple fact. Only one company, Glock Inc, is making parts off of a drawing. Everyone else is making parts off a measurement and hope.

Testing with new barrel

Fortunately for us, we could step this back. Glock does now make and sell factory threaded barrels, and at very respectable price. For $155 they are available right from the Glock Factory Store. This seemed like a very reasonable attempt to make our Polymer 80 work.

And unfortunately, was once again to no avail. The factory Glock barrel did improve our rate between stoppages, but not enough to call this build 100% reliable. We are still having malfunctions at a rate of about 1:25, which is absolutely unacceptable in this day and age.

Solution? no idea.

This was a fun build process, no doubt about that. And one I would recommend if you are into tinkering. But it just didn’t perform well enough to trust, for any serious purposes. I would welcome the comments if you have made a Polymer 80 that ran flawlessly, and we will tinker with this one a bit more over the next year as time permits. But for now, we have to call this one a bust. For defense or combat, my “Glock” is going to have to be stamped Glock. It might be magic in the water down there in Smyrna, but whatever it is it’s working.

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About the author: Clay Martin is a former Marine and Green Beret, retiring out of 3rd Special Forces Group. He is a multi-decade and -service sniper, as well as 3-Gun competitor and Master ranked shooter in USPSA Production. In addition to writing about guns, he is the author of “Last Son of The War God,” a novel about shooting people that deserve it. You can also follow him on twitter, @offthe_res or his website, Off-The-Reservation.com

{ 24 comments… add one }
  • Amado leon November 25, 2020, 12:50 pm

    I can’t see building one you really don’t save any money and then not being reliable . its only a matter of time when the ATF will out law them any way.

  • StraightShoota November 24, 2020, 1:19 pm

    The first one I built runs like a sewing machine. I since purchased 4 more and have built 2 of them. There are so many companies making parts, it is difficult to discern whether the parts kits you are getting are going to be reliable or not. I ended up buying a new G20 because I could not decipher where the pain points were in my build. I switched out the lower with a factory lower and there were no issues.
    I have taken the gun to people who know a lot more than I do about gunsmithing and even they were unable to diagnose the problem.
    I started down the Ghost path because I just did not like the US Gov in my business. However, a gun that does not run EVERY time, is worthless in my opinion. I am hugely disappointed in particular because my first build was excellent.
    Thank you for your candor Clay. This story needed to be told. It has more to do with the parts than the builder….

  • Don from CT November 24, 2020, 8:57 am

    As someone who started shooting Glocks in IDPA in 1998, I have a lot of experience here. I can see the appeal. The P80 glock frame looks to have everything a glock fan could want in a new frame. Higher grip, undercut trigger guard, no bump, etc.

    But the reality is that you are taking a proven system and making it into an unproven system. Some guns run flawlessly. Some don’t.

    Do you really want that kind of uncertainty in a carry gun?

    I don’t.

    The Gen5 removes a lot of the criticisms of the Glock. Get a Gen5, undercut the trigger guard, install the beavertail grip adaptor and have at it.

    One other thing. My favorite barrels for the Glock are KKM. I’ve got one in my G34. My wife’s G34 has a stock barrel. The chamber as well as overall general fit of the KKM is much snugger in every way.

    If I plonk test my reloads there are rounds that will chamber easily in the Glock bbl but will be snug in the KKM.

    I’m not a fan-boy. Just a gun nut with some mechanical engineering background who appreciates the compromises inherent in any firearm. Glock has always erred on the side of reliability. I’m good with that for a carry gun.

  • Cris Figueredo November 24, 2020, 1:06 am

    Hi Clay
    What was affecting all the ones I’ve seen, are the rails…..they always need to be ground and sanded down…..the way to make sure they’re fine, is to run the empty slide on the empty lower….. the lower with only the rails on it…..until it doesn’t move like butter, it won’t be 100% reliable.
    The second thing I found, after screwing with the spring clearance, like other comments have shown….is that they have never worked good for me when running factory recoil springs with the plastic rod….every single time I’ve had to use aftermarket stainless captured guide rods…..don’t know, maybe the plastic ones flex in a way that affects them, but the stainless ones always work great….same rates.
    After that, they have been 100% reliable, even with 6” slides and in competition.
    Hope that helps…..good luck…..swallowed your Prairie book in one swoop on my flight to Alaska, loved it, learned a lot…..recommended it to all my friends.
    Best Regards

  • Gene Stephens November 23, 2020, 2:13 pm

    Clay, I think the problem is your build quality may be a little rough, coupled with perhaps an incompatible part or two. Polishing out your cuts is essential. Don’t be afraid to fine tune that frame some more.

  • John November 23, 2020, 1:14 pm

    I Have a serialized p80 frame so all I had to do is add parts. I had same issue,put lighter spring,different mags and numerous other things. I found ultimately polishing the rails down a tad and polishing and lubing slide fixed my problem

  • Aramfan November 23, 2020, 12:17 pm

    I did an original p80 and put a stock 6″ upper on it. I had the rear rails too tight, had to file them until the slide had a little play. Added a trigger upgrade, it 100% reliable and is lazer accurate! I hand filed the rails completely, no power tools.

  • Sky Buster November 23, 2020, 10:07 am

    Semper Fi Clay!
    I built a P80 Glock 34 and through app. 2,500 rounds the gun has not had a
    single malfunction. I initially installed a Brownells match barrel but it was no more
    accurate than the factory barrel. I can’t stand the Glock grip frame but the P80
    is sweet.

  • Stephen Graham November 23, 2020, 9:36 am

    I wish you had your own channel, Clay. In this build, it looks like you’re having stovepipes (?) After a couple hundred rounds, I had them in my P80 build. Have you considered: 1) lighter recoil spring. 2) “Fail Proof extractor. ? I had stovepipe in my P80 and changed both simultaneously, so I don’t know which one did it, but it resolved instantly.

  • TexDad November 23, 2020, 9:33 am

    So my success with mine, I think, required two critical steps. First, all the polymer sticking above the deck on top and in the spring channel was chased down absolutely flush and smooth. Screw the jig, it’s just a guide as far as those operations go. I got it perfectly flush.

    Second, I took lapping compound to the completed slide, barrel, and locking block. Then assembled, then worked the action until the compound broke down, then cleaned it, then painted in some more and did it again. I kept on until the action was buttery smooth.

    Mine, even with all Gucci parts, has been totally reliable.

  • Adam W November 23, 2020, 9:05 am

    I’m leaning towards the mags (seems like you were as well by reloading and running the same mag that ran 100% in the first attempt). Are they marked so you can try to weed out the “bad” one? It may be that there is one or two mags the gun just doesn’t like. The mag(s) may work fine in your factory Glocks but just not in this build. Gotta be frustrating but I have confidence you’ll work it out. Great segment.

    • Slim November 27, 2020, 10:42 am

      Very easy, magazine and\or guide rod spring. If your using the junk OEM guide rod of her that’s jour issue! If your using a metal guide rod like ALL glock users should ALWAYS use them try lowering the spring to a 15# instead of the 17# your currently running and for sure fix your issue! Check drill holes since I built at G17 and the rider jig I got was WAY off and had to get it exchanged along with the frame for free after I if course had to take so many pictures and prove I’m not a moron who can’t build a glock which has to be the easiest gun to build as a kid I bet could build one of you just showed him or her! Three pins people…. Can’t be much if the uppers moving freely along with the trigger and safety depressive plunger and trigger bar are working as they should would just leaves the guide rod and or magazines. Barrels fine since it feeds done clearly. Barrel has nothing to do with a stove pipe!

  • Bob November 23, 2020, 8:29 am

    For my nickel, I think it would be a mistake to use one example as an indicator of whether something is good or bad or somewhere in the middle. One example is not a trend. I recommend you build two more and run them through the same regimen and see what results you get. Possibly have others you trust build the other test guns. My guess is that Polymer 80 would even donate a few for your test. The other maker of these, 80 Percent Arms, is going to impacted by the fragmentation of this article because of the similarity of the design. You better get a few of those also to test. Looking forward to the follow up articles. Keep up the good work.

  • gerard L November 23, 2020, 7:34 am

    i have a 40-23 that had the same problem but fixed it by cleaning out the barrel pocket better and of all things used bees wax on the rails, end of stove pipe. PS could not hit the side of the barn with it. Pick up a ss80 gl43 and fine tune with rotor tool and hit man size targets out to 25yd with no stove pipes or jams. About a 130 rounds break in so far.

  • Dave Pastorius November 23, 2020, 7:33 am

    I would suggest a process of eliminating variables.
    Swap out complete “upper” with another Glock. Did the jam move to the second Glock? If not, swap out one part at a time (returning the swapped parts if it didn’t affect the jam) until the jams change to the 2nd Glock

  • Rich November 23, 2020, 6:33 am

    Most of my problems have come from the recoil spring rubbing on the frame. It slowed the slide down enough to cause cycling issues, most notably, the slide not locking home on the feed cycle.
    Took quite a bit of Sharpie and sandpaper to get reliability.

  • Greg November 23, 2020, 4:36 am

    I’ll buy it if you don’t want it.

    • Big Al 45 November 23, 2020, 9:23 am

      You do realize he can’t do that? Are you familiar with the laws concerning ‘home/self build’ (alleged ghost) guns?

      • S. Todd November 23, 2020, 2:34 pm

        Of course you can sell a homemade gun. There may be an issue if you built it with the intent to sell. But, if you built it for yourself and then later decide to sell it (because you can’t get it to work reliably, for example), there is nothing stopping you. If you go through an FFL, they may want you to engrave a serial number on it, but I do not believe there is any requirement to do so. A person to person transfer is no problem.

        • Don from CT November 24, 2020, 8:52 am

          S.Tod is absolutely correct. A home made non-serialized gun can be resold. If selling it was not the intent when building the gun.

  • Garren Forth November 23, 2020, 3:53 am

    I’ve built 4 Polymer 80’s from full size to subcompact 9mm to .45. I live in an ant gun state and didn’t want paperwork on my guns so when the inevitable confiscations start they can’t prove I have them. Besides I do enjoy putting them together as it helps to understand how things work.
    With regards to reliability I haven’t had any issues with mine. Granted I don’t burn boxes of ammo every weekend but mine shoot accurately and so far no malfunctions. I highly recommend anyone to try building their own as it’s rewarding and fun!

  • Christopher Mace November 22, 2020, 7:35 pm


    Interesting that you’re having some issues. The P80 build I did a while back has basically been 100%. But I also went basically stock, figuring that I would decide on some upgrades later. I have a few hundred rounds through it, but I don’t have any real wear to speak of internally. If your holes are off, all is not necessarily lost. You could fill the holes with epoxy(make sure you completely fill them so the drill doesn’t walk) and redrill them. Yeah, it’ll probably look rough, but if you’re careful, it’ll work.

    Good Luck!

    • michael hess November 23, 2020, 9:10 am

      you are absolutely right. fill the bad holes with jb weld and redrill them but i’d suggest using a new or different jig otherwise you may very well get the same misdrilled hole(s).

    • Big Play November 23, 2020, 9:18 am

      Credit to MGB for fix:

      • Apex Failure Resistant Extractor Gen 3
      • Glock 26 Gen 5/19X Gen 5 Extractor #47021
      • Non-LCI Plug (Brownells)

      Hope this helps!

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