It’s Still Perfectly Legal to Build Your Own Handgun…And You Should

Previous Post
Next Post

By Lee Williams

Americans have been making guns in their homes since before there was a United States of America – but not this American.

My gun-building history was nonexistent. I’ve replaced some furniture and muzzle devices on a few AKs, but that’s about it. So, when David from 80% Arms called and said he wanted to send me a pistol build kit to review, I thought he’d called the wrong number. I told him I’d never built any firearms and knew nothing about the process.

“Then you’re perfect,” he said. “Give it a try. You might enjoy it.”

A few days later the GST-9 pistol kit arrived in the mail – in the mail. There’s something almost nostalgic about getting a gun – albeit an unassembled kit and not a legal firearm – shipped directly to your home.

Due to ATF regulations, the router jig and frame rails were shipped separate from the GST-9 frame. ATF’s rules currently require the end user to purchase one jig for every frame they build, and the pistol’s frame rails are only included with the jig.

Like everything the ATF does, the rule makes absolutely no sense. However, this will change soon with the release of the GST-9 Infinity jig, which will include multiple rail pack options.

I should point out that a federal court in Texas issued an injunction against the ATF, which allows 80% Arms to continue operating unabated. The company posted a Q&A page on their website that answers all of the questions I had about the ATF’s infringements on their civil rights and business practices.

They yave also established a legal defense fund, because the federal shenanigans are never-ending. Whether you buy a kit or not, please take a look at their legal defense fund and consider supporting them. After all, they’re fighting for all of us.

Established in 2013, 80% Arms is the leading 80% manufacturer in the country. In my opinion, they produce incredibly reliable and effective components for the home builder. For example, they created the first 80% router jig which revolutionized the home building process because it allows anyone from experienced engineers to first time users like me to successfully and quickly mill out an 80% lower using common household tools.

Originally based in Garden Grove, California, the company has moved to a new and much larger location in Fort Worth, Texas, due to the influx of anti-gun legislation in California. They just soft-launched a new showroom at their Fort Worth store.

In addition to the GST-9 they sent me, they sell jigs, tooling for the jigs, their own router jigs designed specifically for milling 80% lowers, 80% AR-15, AR-9 and AR-10 lowers, uppers and a ton of parts and accessories.


I read nearly every instruction manual and customer review on the 80% Arms website — and there are a bunch — to get ready for the build. The tools I needed were minimal. A hand drill would have sufficed, but a drill press is recommended, so I bought a table-top drill press from Amazon for around $50.

Courtesy Amazon

You should also have a GLOCK punch, a mallet and some fine-grit sandpaper. If you’ve never fully disassembled a GLOCK or installed a lower parts kit – I hadn’t – there are numerous videos on YouTube that will walk you through the process. I’d recommend watching them several times.


My build kit came with a polymer jig, a MOD1 frame and the Wraith slide.

The frame secures rigidly inside the jig with just screws and nuts. There’s no movement at all. It’s locked, and I’m told that 80%’s new metal Infinity jig is even better, because it’s durable, reusable and made of 6061 billet aluminum – the same material as some of their lowers.

The new metal jig is “backwards compatible,” so it will work with V1 and MOD1 frames, while producing consistent results every time. The GST-9 Infinity Jig and its rail packs will be available for purchase beginning Friday, March 24th.

The first thing I noticed was the aggressive stippling on the “gas pedals,” located on both sides of the frame, spaced perfectly for your weak-side thumb.

80% Arms Wraith slide
80% Arms Wraith slide

The rear rail is now a two-piece design, which prevents builders from accidentally bending the rail while hammering in the retaining pin.

The frame came with two different grip modules that can be switched out by removing two pins. The smaller module will accept G19 magazines, and the larger module takes G17-size mags. In my humble opinion, this is a genius design feature.

The Wraith slide came fully assembled, and it’s a far cry from a standard G19 or G19 clone slide. Some call the GST-9 the “Gucci GLOCK.”

The match barrel is fluted. The slide has forward serrations on the sides and “Dragon scaling” on the top, which makes press-checks easier. The slide has lightning cuts to reduce recoil. However, the best feature is that it comes optic-ready with an RMR cut, which also accepts Holosun and other brands of sights.

All the edges are well beveled, so there’s nothing to snag or catch on clothing during draw strokes.

The build

The build was easy – a far cry from what I expected – and fun.

Once the frame was secured inside the jig, I drilled out the three holes on each side of the frame, rather than drilling all the way through the frame from one side, which isn’t recommended.

Once drilled, I switched to the “cutting tool” drill bit, which is included, to grind off the four top tabs and one front tab – extra plastic, which I assume was left over from the molding process.

Some builders use a scalpel, X-Acto, or a sharp knife to cut off the tabs, but the plastic seemed a bit too thick for that. I was somewhat worried about grinding off too much material, but the jig prevented this from happening.

Once the plastic was removed, I popped the frame out of the jig and sanded the areas where the tabs were until they matched the frame.

After I was satisfied, all that was left was to was to insert the lower parts kit into the frame. I’d like to say I did it right the first time, but after installing the parts kit and slide, I noticed the connector was still sitting on my work bench. The slide of course wouldn’t come off, so I used a lifeline and called a GLOCK armorer friend who talked me through fixing my mistake.

After some cursing, I had a completed pistol.

Total build time was around four hours.

Range report

80% Arms claims their handguns need a few hundred rounds and plenty of lube before they’re broken in. They recommend firing 50 rounds, swabbing the gun down with lube, firing another 50 rounds, applying more lube, and so on.

I lubed mine normally, loaded four mags with Igman 124 gr FMJs and fired them all off without a single malfunction. It was exactly like shooting an OEM handgun straight out of the box. Three hundred rounds later, I still had zero malfunctions. The “gas pedals” on the frame proved to be an added bonus.

After dialing in my optic, accuracy was better than any GLOCK I’ve shot before (although I’ve never shot a GLOCK with a match barrel).

The GST-9 is accurate and reliable. I was able to keep controlled pairs and controlled threes inside three-inch dots at seven yards very easily, which is about all I can ask of an EDC handgun. About half the time the groups were one ragged hole.


The MSRP for the kit I received is $749, although there are cheaper kits available that don’t come with the tricked-out slide. Note: 80% Arms build kits sellout quickly, so check their website for availability.

I wasn’t ready for the finished gun’s reliability. This is a reliable carry gun, and I will add it to my stable of EDC and backup guns.

The good folks at 80% Arms are on the frontlines of Joe Biden’s war on our guns. That alone is reason enough to give them our support. But as promised, the build process was fun and highly addictive. I just received my second build kit, which will be built with the new metal GST-9 Infinity jig.

Bottom line: If you’re looking for a fun build and a dependable and accurate handgun, look no further than 80% Arms, but keep in mind, you won’t be able to stop at just one.

Previous Post
Next Post


  1. “The smaller module will accept G19 magazines, and the larger module takes G17-size mags. In my humble opinion, this is a genius design feature.”

    I agree completely. In contrast to the fanbois practically ej@culating over the fact that one could buy a G47 and build a hybrid with a G17-length slide and G19-length grip (by filling out two 4473s and having one wasted franken-spare) 80% Arms is making it possible to do something similar – by swapping out a $5 piece of plastic!

  2. There is a degree of confusion out there with this. Going out and buying all the parts including the lower receiver for an AR15 and building it at home is still perfectly legal. Many people do this. This has nothing to do with what this article is talking about. This is an article about building a firearm using 80% lowers which is a very different thing. Both are completely legal but these are two distinct activities.

    One requires a 4473 and the other doesn’t.

      • Are you really going to tell me that you don’t see the 4473 being used when purchasing a Aero Precision lower receiver? Really?

        • Sorry, where did you say anything about an Aero lower in your post? This is about 80% lowers. Of course an Areo lower will require a form 4473. If I miss construed I’m sorry.

        • That’s my point exactly.

          You and I read this and understand it but that majority of the people out there (the voting public) don’t.

          I can “build” a gun and never touch a 3D printer or anything 80%. Many people actually think that when we talk about “building a gun at home”, it’s all about 80% stuff or 3D printed plastic. People really need to understand the distinction.

        • What it boils down to is we shouldn’t have to register a damn thing. I fully agree.
          Besides trademark infringements I should be able to manufacture lowers with Aero imprinted on it with no serial number
          and have it be perfectly legal.

  3. Building your own gun is legal!

    Unless you live in CA, where the Dems have codified into law the requirement to register your blank frame with CADOJ and request a serial number which must be engraved on the gun (but it’s okay kids…they insist it’s not “registration”), build them single-shot, and other restrictions. And if you’re building an AR instead of a P80, it’s even worse. Furthermore, if you live in certain areas (such as Los Angeles County), purchase and delivery of blanks is illegal all by itself.

    Democrats suck.

    • Haz,

      “Democrats suck.”

      Strong language coming from you, Haz.

      Welcome to the “Thoroghly, utterly, and irrevocably pissed-off club”.


    • While in the “free” state next door, we don’t even have that option.

      100% agree on your closing point.

    • “Furthermore, if you live in certain areas (such as Los Angeles County), purchase and delivery of blanks is illegal all by itself.”

      ‘That’s what friends (in free states) are for’ :

  4. California does not allow home built firearms without first obtaining and inscribing on the frame a unique werial number issued by the DOJ after the completion of a backgro9und check. California has been actively attempting to eliminate the entire 80% business, including pending bills that will ban 3D printers and a number of milling machines. I think they call this “Freedom from Fear.”

    As if.

    • i doubt the 3d printer ban is going to pass, because the film industry is going to oppose it…

    • “including pending bills that will ban 3D printers and a number of milling machines”

      I’ll be very surprised if that passes…

    • New Jersey and New York do not allow home-built firearms at all, totally banned (New Jersey even bans homemade black-powder muskets, FFS, they do!)
      Around here, the local politicians call them “ghost guns,” and the nightly TV news makes a huge deal every time the NYPD or NJ State Police conduct one of their frequent “ghost gun raids” where police (tipped off by an anti-gun informant) search somebody’s home and find a couple oh-so-scary “ghost gun parts” or a “ghost gun kit.” Then the NYPD or NJ State Police throw the poor hobbyist in jail, probably giving him a longer prison sentence than they give to rapists and murderers. And the TV-news viewing public swallows the news story hook, line, and sinker and says, “Thank God Mayor Eric Adams and Governor Phil Murphy are taking those oh-so-scary, oh-so-dangerous ghost guns off the streets of New York and New Jersey!” SMH, from the breathless way the New York TV news reporters sensationalize these “ghost gun kit” arrests, you’d think they’d just taken a million pounds of heroin off the streets, but it’s just some poor hobbyist’s home project. It makes me count down the days until I can retire, leave the People’s Republic of New Jersey, and move to the United States of America.

      • Fun fact: Our former CA Atty General Xavier Becerra (now Obiden’s Sec of HHS) coined the term “ghost gun” years ago in what he publicly stated was an attempt to entrench a term into the national psyche the Left can use against gun owners. And viola! he was right.

        I think we should start using the term “ghost budget” for politicians who knowingly spend money they don’t have.

  5. I just wish they carried MUPs and build kits for the Sig P320. Kudos to them in their fight to keep distributing 80% kits. I keep sending FPC funds in this fight as well as for the idiotic re-categorization of AR pistol braces as a controlled firearm. More 2A fights out there than I can keep track of, but folks out there, do something about it. Write your congressmen (FPC has a website that makes this easy and is categorized by issue and state) and donate, even if its $5 to help these orgs invalidate these unconstitutional laws.

    Like I’ve said earlier, I really would like to see someone take this farther and actually press charges for removal of office (at least) and being barred from future office to these politicians that consistently push through and vote for unconstitutional laws and violating their oath of office. If they can’t draft or vote properly for laws that are constitutional, they have no business having that job – it means they are unqualified for lawmaking public service. Period.

      • Contrary to ads calling 80% “Untraceable” and providing the groundwork to regulate them the 80%s are traceable by rifling, etc. Your fingerprints are on the firearm, your DNA is stuck in the nooks and cranies, and there is your shipping address, and your pals who will sing like canaries to avoid being involved should the firearm ever be used illegally, etc.

        80% were a very good thing for DIYers testing their skills and saving money. The “Untracable” sales pitch stupidity flushed the latter and almost the whole shebang down a toilet.

        • Um, Debs…even though I got my 80% frames before CA started restricting them, I had the foresight of paying cash in person from a retailer or asking a friend to buy online for me. Totally legal at the time.

          And I challenge anyone to get usable prints off of an aggressively stippled grip.

  6. For that kind of money, I could purchase one of those Bear Crerk 10mm carbines, which I very much want. But some debt elimination is the highest priority.

  7. I think a lot of people are missing the point. The up front price for the jig that you can use over and over again pays or the NRE of the jig. After that having a firearm that Daddy Gov doesn’t have paperwork on is the plus.

    • Muck,

      Not missing the point at all.

      I am halfway through a 2-year project to rid my home of toxic mold that nearly killed my wife. Doing it meself because the pros would cost me over $100k and not do as thorough as job as me. (I spoke with some, got estimates, reviewed their procedures). My house…I care…my wife’s health…I will do a better job. Still working full-time, so evenings and weekends. No time to build guns…barely time to get to the range. A matter of priorities.

      But I do get your point.

      • Life Savor-
        I’ve had sinus problems from whatever they sprayed me with in SE Asia. Black mold grows inside the walls of my house and drives my sinuses batty. Concrete slab is porous, too, so the house is irreparable.
        Please publish knowledge on how to combat the dirty stuff.
        I am now 54 hours out from getting up after my latest VA sinus surgery! And 50 years plus 362 days past the day when the migraines from my sinuses started.
        But hey, I’m mucho thankful that they decided to give me the surgery! ENT Physicians claim it’s ”not indicated” when you don’t present with infections.

        • 05Banana,

          I am sorry to hear that you and your home are infected with black mold. It is dangerous, highly toxic. Likely, you have other toxic species, also. We had/have several. but we are slowly winning the battle. Since I am not a ‘licensed’ mold removal professional, I can only tell you what I am doing. The 3- letter agencies hunt and persecute unlicensed folk who give advice.

          It will take me a couple of days to write the procedure. So check TTAG over the weekend. Alternatively, you can text your contact info to my cell (610.504.3640) and I will send it to you privately. It will be several pages of text. I will tell you what I do for the walls and for my sinuses. Anyone with toxic mold in the house has it in their sinuses.

          Best wishes!!

      • Lifesavor,
        Please use every freaking precaution doing that work and I pray you and yours remain safe.

        • Muck,

          Thank you! Yup, I have better gear than some of the remediators I spoke with. Again, thank you!

    • The only reason I never bought a 3D printer was for the fact that the plastic is one way. Like regular printer and the never ending need to buy ink. You can’t take something you print and melt it down going back to the spools. It becomes such a waste. I would love to turn Tide laundry detergent bottles into AR lowers. It’s the logical conclusion for where these machines need to go. I’m surprised that the environmentalist greenies out there don’t push for this. Especially given all the water bottles floating around.

  8. How/where to you purchase that you don’t end up in a database??? 2. Its a Gluck clone (NOGO)

  9. “So, when David from 80% Arms called and said he wanted to send me a pistol build kit to review, I thought he’d called the wrong number.”

    So, when David from 80% Arms called and said he wanted to send me a pistol build kit to sale…


    seriously, reviews have become nothing but basically sponsored content shilling sales pitches with a little ‘folksy’ vibe thrown in. Its a nice review and all, ya did a good job with it …but its really shilling plus its pimping for donations. I’m pretty sure David from 80% didn’t call the wrong number to send you a $700.00 gun kit and I’ll bet like most “influence reviewers” your ‘firearms’ collection of stuff is mostly composed of free things you got from other companies who “mystically” called you by mistake.

    “I thought he’d called the wrong number.”

    Its not really “Whoopsie…wow I got lucky that David just happen to have called me by mistake to give me a $700.00 gun for free.”

    • 80% Arms is the driving force behind VanDerStok v Garland that will toss 2021-05F. Buy from them if government over-reach bugs you and the 79 pages or so of the rule used to redefine one sentence in the GCA undemocratically should upset you.

  10. Oh. An 80% lower.
    I was hoping for an article about building a handgun lower from a block of steel.
    Or how to rifle a barrel blank.
    At home.
    That would of been interesting.

  11. Handgunm,,,nah.
    I’m building an F16 and a UniverseEndingPerpetualFussionNuetrionoBlomb. I was just going to blow up the Earth but when I found out Musk might escape to unknown goldilocks planet I decided just to vaporize the Universe. cant take any chances with you humans. You always seem to come back and fck everything thing up for everyone. Hindsight is 20/20 , We should have kept Neanderthal and trashed Homo Sapiens.
    Fuk Noah

  12. It’s great that you described how to build our own handgun and why we’d try it. I spoke with my brother a few days ago, and he mentioned he’s interested in custom-building his next firearm, so I’m sure he’d love to read your article now. Thank you for the information on having fun when putting together your handgun’s build.

Comments are closed.