Ruined Your 80% Lower? The Good News Is You Aren’t Alone | Gun Guy Thoughts

Let’s face the facts, it isn’t hard to ruin something if your primary tool of destruction is a Dremel. Over the years, table top gunsmiths have ruined more firearms than I care to think about using JB Weld, paint, welders and even carefully applied Duck tape to hide their sins. But what if you didn’t run a firearm at all and had only ruined your 80% receiver?

Post it to Facebook of course!

I was so graciously added to the 80%Builder Facebook group by my friend Yale to check out some of the carnage. The next thing I knew a few hours had passed and I had a small collection of photos that make me giggle a bit.

Sure there are some builds on there that look like they turned out just fine and there is nothing from with someone building an 80% lower if they feel like it and it is within the law. I think the failures are kind of funny but don’t know enough about machining or what happened in each case to provide any insight past “Would ya look at that. Just look at it.”

First up is a lower build that looks like it was sorta going in the right direction until the bottom of the trigger pocket broke through. Could this be a dull drill bit? Probably. It could also be a very poor quality 80% lower that was made from recycled Matchbox cars.

I just don’t even know what to say about this one ….. I kind of wonder if the builder punched through the bottom of the lower and then decided to keep going since there was no way that he could jack it up further.

The importance of making sure the jig is positioned in the correct place and not crooked is painfully apparent in this one. I have a feeling that the selector switch might be a bit sloppy.

I. Just. Can’t.

It looks as though the builder used a drill bit designed for woodworking or maybe even the wrong size? I am not really sure, but it hurts to look at. I feel like the money spent on this lower and the tools used to gnaw the trigger pocket would have been better spent on a factory produced lower.


Now not all of the receivers are ruined in this post, although I feel that the Glock frame below is a little bit ruined. Sure it isn’t anywhere as jacked up as the AR lowers above, but the windows on the side of the grip are pretty dumb. The weight savings is so small that the user would never even notice if they hadn’t been cut. The actual stippling work isn’t complete poop though.

Not all 80% receivers are complete trash, this Type 91 build is pretty rad I think. The only thing that stops me from buying a ton of these and going on some crazed clone building spree is the fact is the lack of space in my gun safe.

Personally, I don’t see the allure of MOST 80% lowers (clone lowers excluded) even though they allow some people to acquire a rifle in an area that is otherwise hard to do so. I guess living in Texas has jaded me a touch.

Being able to buy the things I want without crazy legal hassles is nice.


  • hking

    First one looks like the guys drill depth stop failed or the bit slipped down in the chuck.

  • nova3930

    If you don’t have the proper tools, you probably shouldn’t be working in metal. Even a cheapo chinese mill drill is better than some of the drill press and/or router solutions I’ve seen for doing 80% weapons…

    • DrewN

      With good tooling and proper technique you can turn out some nice work on a cheap mill. Just have to be realistic about tolerances. My neighbor cranks out pretty sweet motorcycle parts all day on one.

      • nova3930

        Yah, operator matters more than anything. The dovetail column mill/drills can actually work pretty well as long as you remember they wander a bit in the Z axis. Long as you compensate you can turn out decent parts.

      • Flounder

        I don’t think any of these involved a mill. This article should be titled, things that go wrong when you use the wrong tools.

        • Gary Kirk

          Probably included the use of, but not limited to.. A DeWalt 18v cordless drill, else cheapo drill bits from Home Depot, and the ever so accurate electrical tape depth gauge..

        • BryanS

          Im going to bet a lot of them involved holding endmills in a drill and trying to go sideways.

    • Flounder

      SO much this!

      All the AR lowers look like the chuck/arbor came loose and fell down into the work while still spinning and the people using it had no idea there was even an issue.

      • Jim_Macklin

        It looks like some of the twist drills were sharpened off center. A twist drill, even in a jig won’t drill a round hole if the point is off center and the angles and relief are not identical.
        Since the whole point of 80% lowers is secrecy, don’t buy anything with a check or bank card. Better avoid hunting licenses, magazine subscriptions to a long list of magazines that cover machine tooling, gun making, metal forging or politics.

        • mazkact

          The range I am a member of went to pay pal only for paying annual dues. Pay pal made their book keeping easier(we have a LARGE membership). I don’t like it but put up with it. Some friends of mine dropped out when they could no longer pay their dues in cash and I understand this. Some reasoned that paying dues to a rifle range with pay pal may get them on a “list” and I understand that but to me it is false logic. When things like this come up the first thing I ask is “have you ever bought a hunting license ?” if the answer is yes I say quit worrying, it’s too late.

          I do understand trying to fly under the radar and the older I get the more I try to. Recently I removed all my “cool” stickers from my vehicles as I saw them as an invitation to break in , that and got tired of being cut off and tail gated by Prius drivers with coexist bumper stickers 😉

          • You’re missing the point.

            It’s not be necessarily about staying ‘under the radar’ – it’s also about pride of production, knowledge acquisition, and some people just want to do it that way. I’ve done different 80% firearms for different reasons – EXCEPT for the ‘under the radar’ one.

          • mazkact

            I really do understand your point. I am a Machinist by trade and if I had a decent milling machine at home I could not resist doing it. I do many “gunsmithy” things with my drill press and hand tools but finishing a lower would not be one of them.

        • Brian

          Building for secrecy is an idea that came from people who dont build themselves. The amount of people who build for the experience far outweighs the people who do it to be discrete. I have quite a few custom builds I’ve done myself as well as purchased firearms.

    • Kelly Jackson

      You’re kidding yourself if you’d take a junky Chinese mill over the router method. A Porter Cable with a proper jig works considerably better than those wonky Harbor Freight specials.

      • nova3930

        Even a mill drill can hold consistent tolerances dependent on the care taken by the operator, something a router just can’t do. No matter what jig you use the router just isn’t stiff enough. You get too much tool deflection to maintain tolerances. Then again I learned to work in metal the correct way instead of just slap dashing

  • PK

    Clones and exotics are the reason for 80% lowers, that and the fact that simply building guns is something of an act of defiance, even now.

    Still, clones of otherwise unicorn guns… that’s where the real fun is.

    • Sunshine_Shooter

      Someone mentioned that being the window-cutter’s true intention.

      • PK

        I figured as much! I asked myself what I’d do with a frame like that, and that was the answer I came up with. I might actually have to do that, I still have a pile of those frames.

        • Sunshine_Shooter

          It actually has grown on me, now I want to see how useful it really is.

  • PeterK

    Desire to ever make 80% lower nearly extinguished. 8|

    I kind of want to do a 0% lower sometime. If I ever get access to tools/mill/stock.

    • Michael Lubrecht

      I’ve done one 80% and successfully completed several 0% lowers. They are a lot of work, requiring multiple setups and careful measurement. My worst mistake on one was boring the hole out too large for the buffer tube. Transposed a couple of measurements in my head. I could put a bushing in and fix it, but not worth the effort.

      • PK

        Helicoil! Do iiiit!

        Seriously, if that wasn’t one of your first operations, fix it and run it. Why not? That, or close up the buffer area, and make a manual action or piston gun.

  • Michael Gallagher

    I got an AR lower that I made from an 80% kit that did not come out real pretty. Replaced it later and it now sits, stripped down, in a drawer waiting on a gun buyback in my city so I can trade it in on a gift card worth a few times what I paid for it in the first place. Finished ones are considered firearms. So it ought to work……………


  • codfilet

    Even the finest cooks have ruined a few dishes before they got it right. Even the most skilled toolmaker was once just starting out as an apprentice. You get good at something through practice and experience, and making some mistakes just goes with the territory.

    • PK

      The ability to swallow your pride and admit when you made a mistake, especially when you can laugh at just how badly you messed up with something like this, is a good sign that you’ll go far. I don’t think any of the pictured attempts being ribbed would have the builders upset.


    80% lowers are a good concept but you’ve got to be out of your goddamned mind if you think I’m gonna pay the same price (or more) for one than an actual lower. 25 bucks, I’d own a dozen. 85 bucks, yeah eat a bag of dicks.

    • nova3930

      No lie. Dumbest idea ever to pay more to do 20% of the work. Although I am interested in taking a raw forging and turning it into a lower. That’s just for the machining challenge though….

      • PK

        There’s a fellow on slickguns that advertises raw forgings (upper and lower) once in a while. They offer a fun time in the shop, along with near endless possibilities for customization. I think he’s got a 10-piece minimum order, but the price is extremely reasonable.

        • nova3930

          Dsarms has or at least used to have them on their website for 19.99 been a while since I looked.

          • PK

            I think I bought ten raw forgings for $100 shipped. That’s what I mean by it being a really good deal.

          • nova3930

            That is a good one. Looking around noreen has them for like 13 bucks. Might snag one to have…

          • PK

            Noreen, as in the 30-06 and longer caliber ARs? Good company, good people. I’ve visited them in person, everyone I spoke with was very friendly and helpful.

          • nova3930

            yep one and the same. looks like all their prices are pretty reasonable

    • PK

      Wait, when did 80% lowers get to be that expensive? Last time I bought a box full, they were $27 shipped.

      • ORCON

        Was that back in 2006?

        • PK

          No, it was in March of 2015, I bought them from Tactical Machining.

          They seem to have cosmetically blemished 80% lowers for $29 right now, bare and unblemished for $34, and anodized and unblemished for $44. When they’re in stock, anodized/blemished are $34 as well.

  • Harry’s Holsters

    I’ve got an 80% paper weight that has been sitting on my desk since 2013. I bought it during the panic. Considering I can buy an Anderson lower for $50 locally it makes the 80% lower useless. I’ve got to be on so many lists that isn’t a good excuse to do. The more people we get on those lists the better as it makes them ineffective if they ever tried to use them.

    • nova3930

      The idea of lists always makes me laugh. ATF can’t even maintain the NFTR adequately for the much smaller subset of NFA items. Don’t know what competence anyone thinks any portion of the Fed Govt has to collect, compile and digitize all the 4473s out there. They can’t even make their personnel records from different agencies mesh into a digital system.

      • Bill

        ATF “databases” are literally banker’s boxes full of paper records that have to be hand searched by clerks named Mabel and Gladys. Some are stored in shipping containers in their parking lot in Clarksburg WV.

        • nova3930

          And that’s only the one’s the ATF has. Most are stored at the individual FFL and will only go to ATF when the FFL closes. How many you figure were destroyed/lost in some manner before turn over for FFLs that have closed? I know I’ve heard of more than one story of FFLs purposely storing them in a manner to ensure destruction prior to quitting… Sorry mister agent man, my storage shed just burned up in a fire…..

          • Sunshine_Shooter

            Also, I believe those records can be destroyed after 20 years, so the FFL can legally destroy old documents on their own. That may be a complete falsehood, so don’t take it as fact just yet.

          • Alex

            Or when they show up to do an audit and photograph literally every page of your bound book. Then you have defacto registration already. But that’s illlegal. So is mass surveillance but they do that already too and no one cares. Oh well back to TMZ I go…

    • mazkact

      Nothing wrong with an Anderson lower. I really like the ones with integral trigger guards , I put together some nice rifles with them.

      • Longhaired Redneck

        Two weeks ago I bought an Anderson integral trigger guard lower from Sportsman’s Guide on sale for $37.99. I know that I’m already on many lists, so as ‘Harry’s Holsters’ mentioned above, bury ’em with names!

  • Rick O’Shay

    Does anyone make a slick-side 80%?

    • Flounder

      Nodak Spud might? they make a lot of retro recievers. idk about an 80% though.

    • PK

      NDS does, as Flounder mentioned. They tend to do a run only once in a while and they sell to the waiting list/pre-order list first, so get on there if you’re interested.

  • Piraterider

    That Glock frame inst cut for weight savings. It’s cut to run clear mags so you can get a bullet count on the fly. You’re bashing it for the wrong reason. I was privy to the original thread by the owner. They guy who made it thought it a better idea to cut up an 80 than a OEM frame. I think its a pretty cool idea, not everything has to be battle ready.

    • Flounder

      That is actually pretty cool as a fun gun then.

    • noob

      I wonder if strength could be restored by overmolding clear plastic over the windows in the grip?

      • B.

        Yeah, I’d not like all the dirt, dust, and general crud being able to get in there that easy. Some nice clear inserts would help with that.

    • Anonymoose

      Just like a modern ASP! This will be the next thing after Roland Specials.

    • jerome

      Bet the mag added some integrity while firing. Most of the time people fire weapons with magazine or clips in them

      • uisconfruzed

        Other than a Garand, who’s firing what with clips in them?

        • GomeznSA

          Well there are a ‘few’ short magazine lee enfields out and about 😉 and IIRC they are charged via stripper ‘clips’ – or with individual rounds, unlike the Garand.

          • uisconfruzed

            I was acting a bit like a magazine nazi.
            It was the “clips in them” part that had me scratching my head. I’ve a pile of stripper clips from the (10) 5.56 rounds per strip.

  • Veteran for Trump

    I’ve done 4 lowers, but only 3 have survived. The first one was a Gen I Polymer80 that was not reinforced and suffered a catastrophic failure at the rear takedown pin. They replaced it for free, even the shipping, with a Gen II Kevlar reinforced 80% lower which is now in my 300BLK and has not failed. The other polymer lower sits on a shelf in the closet, completed, as a spare or maybe another rifle someday. The last 80% lower I did was aluminum and is my 5.56 AR.
    The failed lower.

    • Flounder

      I have had two failed lowers. Both fiber reinforced polymer. The second, I removed too much material in places and pins wallowed out the holes.

      The first, was also my fault, I used the JP silent captured spring and a buffer spring detent… It snapped right through the rear pin hole. Although, at the time, JP did not include instructions to remove the buffer retaining detent. So… IDK if someone lost the warning sheet or if it was undiscovered at the time.

  • civilianaf

    The Polymer 80 Glock Frame is stupid easy. Not sure how anybody can screw that up. Maybe if you cant operate a power tool, you shouldn’t get to have one? Darwinism at work here? #airsoft

  • Greg

    The Ed Bassmaster reference made me lol

  • Devil_Doc

    Where did that T91 lower come from? Asking for a friend…

    • Mr. Privilege

      I would assume it’s an 80% A2 lower that has been custom engraved. I have seen guys on forums post pics of their 80% A2 lowers that they had milled into A1’s and engraved with the Colt logo and “Property of US Government” markings.

    • Longhaired Redneck

      NoDak Spud has links for engravers and anodizers on their website. The outfits all have the appropriate FFL status so everything can be shipped door to door without any 4473 transfers being required.

  • Haulin’ Oats

    80% GlocK: Impefection.

  • Jim

    Those photos are a good reminder to be VERY CAREFUL about buying used firearms at gun shows or from individual sellers without closely inspecting them. I once just about purchased a used traditional Hawken style muzzleloader from a mom & pop vendor at a gun show. Upon close examination, I found where the previous owner (or someone) had stripped the threads out of the nipple hole and forced in a nipple of the wrong size. If fired, the back pressure would have sent that nipple right into the shooter’s face. The vendor must have been aware of the defect because he got irate at me for pointing it out and tried to get me thrown out of the gun show. After examining the rifle, the gun show officials shut his booth down and according to one of them, stated that they would not book him at their gun shows in the future because they had prior complaints about him. BUYER BEWARE!

  • Jack

    There are three categories of 80% users out there…1) People who don’t want Obama to know they have a gun. 2) Convicted felons. 3) Both.

    • McThag

      4) Nostalgia. To have a copy of the rifle I was issued in the Army right down to the serial number. They certainly weren’t going to let me keep it, so I had to make my own.

    • the_duck

      or you live in a state where you can’t buy a rifle until you’re 21 but can make one from an 80% lower once you hit 18.

  • jerry young

    I did my first 80% AR on a drill press with great results other than my 30 year old Delta table top drill press taking a crap, I bought a new drill press and a Grizzly table top mill, I’ve done 2 more since with great results, the one that broke through you can see perfectly round holes, the guy drilled too deep, then he didn’t mill to the correct depth, believe it or not there are instructions that anyone that can read can follow along with jigs that have guide plates and as long as you use the proper bits and can follow simple instructions they are easy to do, did I mention I had almost no machining experience and a very small workshop, the only reasons I don’t do more is space and money, the 80% lowers are cheap it’s the rest of the gun that cost.

  • Sam Damiano

    I have a few of Bushmaster lowers that I bought for less than some of the 80% lowers I’ve seen. Bought three thinking I’d sell two to pay for one plus shipping on all three, then decided I have three lowers who cares.
    The windowed Glock looks kind of neat for a race gun.

  • Some Rabbit

    So you’re saying you can’t just clamp the receiver between your knees and use a hand drill?

  • mazkact

    But But ifa bye a finneshed 1 da gubmint nose 😉

  • Ken

    Good looking Type 91 80%, but it should be an A1 style lower.

  • Evan

    id have the glock with clear mags

  • mazkact

    “We don’t make mistakes, just happy little accidents.” – Bob Ross

  • BryanS

    I have a vise like that, spent a good chunk of time turning it from horrible to passable, gave up, and just use it to hold things on my desk from time to time. A turd can be polished, but still stinks.

  • jerome

    Put a brass plate under those AR’s and MIG weld those holes up

  • jim

    80% lowers satisfy a need to create. Like tying fly lures, or oil painting. And, not everybody can be like Patrick and just go buy scads of stuff, too.
    As to the hacked up lower: Jig? what’s that?

    • I have yet to see an 80% receiver (aside from an AK) that was actually cheaper than buying a factory made 100% receiver.

      There are valid reasons to do an 80% build — but money ain’t one.

  • jonp

    This is why i bought a few 80% lowers in polymer first to practice on.
    Most do this for the same reason we make our own black powder, cast bullets or cut 2×6’s out of a tree with an alaskan mill and chainsaw. To do it ourselves

  • Bill

    Gomerism isn’t limited to drill disasters either. I remember seeing a guy bring a very expensive AR into the local shop trying to say it was defective because he had tried to put a Magpul trigger guard on it and instead broken a tab because he didn’t use the proper technique when driving the pin out. Oops!

  • markrb

    You can do it on an $80 Amazon drill press with a $40 x-y vise if you take your time, and follow instructions. Oh yeah, a good jig helps, too.