80% Receiver Pistol Build-Can A Caveman Do It?

By Mike Keleher

I love to tinker with my guns, and truth be told, I break more guns in a given year than most people shoot. I then have to fix them. I learn an awful lot that way. Trial and error is practically my middle name. I have learned internal functions, fit and finish and the fact I should not be left unsupervised with power tools while working on firearms-someone will have to pay for the mistakes, and someone else should probably run get the bandages. (Pro Tip: Duct Tape..oh so handy, and we’ve all done it.)

When it came to the topic of 80% receivers and building guns from scratch, I saw them in the news, but was never really interested in building one. This all changed a year ago, when I sent my local state representative an email on some pro-Second Amendment topic, and he wrote back he was hugely anti-gun and from atop his high-horse was even going to introduce legislation to ban home built firearms and anything that had plastic in it.

These home builds are permissible under the federal law, had never been involved in a crime in this state, and this honorable goof-ball (Did you catch the honorable part? Always good to be polite) was going to leislate access away from me and you! Now I wanted one! (A year or so later, that proposed legislation has never made it out of the “liberal dream stage” for passage in Illinois.)

Something similar happened when I lived in California after I voted for some action hero star named “Arnold” to be the governor. After earning millions “being right back” and “terminator-ed” shooting tons of cool guns on screen, he turned around and banned .50 Barrett rifles for no apparent reason. They had never been used in a crime in California, but this whole banning thing might some day prevent a crime…somewhere…maybe…a little bit.

Yes sir this ought to prevent gang bangers from obtaining a multi-thousand dollar 26 lb single shot rifle and using it in the neighborhood! Well, I never wanted a .50 Barrett, and could not envision any type of use I would want one for, but if the government was going to make it illegal, suddenly I wanted one of those too.

I did some research on this whole 80% build thing, and found you get polymer frames for Glock type pistols or lower receivers for AR-15’s which are mostly complete, but you have to do some work to make them suitable for installing parts to build a firearm. The 80% frames do not have a serial number on them and can be purchased without an FFL or registration by anyone who is not otherwise prohibited by federal or state laws.

I also looked at www.ghostgunlaws.com, for a succinct description of laws involved. Under the Gun Control Act of 1968, 18 U.S.C. Ch 44 “Firearms may be lawfully made by persons who do not hold a manufacturer’s license under the Gun Control Act provided they are not for sale or distribution and the maker is not prohibited (a felon for example) from receiving or possessing firearms.” (Another source to look at is the BATFE FAQ’s web page.)

The www.ghostgunlaws.com site also listed the facts it is legal to purchase 80% lowers without a FFL, registration and background checks are not required. It is illegal to build a firearm with the intent to sell without a FFL and it is illegal to sell an unmarked and unregistered firearm. Obviously all firearms must comply with Federal and local laws. Self-Made Firearms must be completed by the Owner with their own equipment and as long as you are making it for your own use and not for resale you don’t have to affix a serial number or ID.

Well, I was interested in making my gun completely from parts with my own tools. Check. It would be just for my own use. Check. Then not created or offered for resale. Double Check.

When I was passing through the middle of Iowa last summer I stopped in at the Brownells retail store and warehouse facility to see the facility and aslo to see where so much of my disposable income ends up. In the showroom I ordered up a kit and some Santa Elf-like employee brought it from the warehouse in minutes and at the front counter I bought a Polymer 80 brand large frame PF45 model Glock compatible 80% complete polymer frame for about $120.  No FFL, no waiting period, just a hunk of plastic and some drill bits. Aha! I was ahead of my dunder-headed local legislator!

I was very impressed with the kit, which consisted of the polymer large frame for either a .45 ACP or 10mm Glock build, a snap together jig that holds the frame in place while you drill three holes in the frame, appropriate drill bits, and a larger bit used to cut out (gouge out in my case) another piece of plastic in the recoil spring groove area of the frame. It also included unique rails the slide would ride on some day.

You also have to cut off/grind off four plastic tabs on top of the frame. That’s it. Drill three holes, cut out and smooth the recoil spring area tab and cut and grind off four plastic tabs on top of the frame. Even a ham handed mallet wielding caveman such as myself should be able to whip this out in about a half an hour! Right? Whooie…I can’t even draw a straight line and the most consistent item I made in high school shop class was saw dust.

(Drill bits are pointing towards the small plastic tabs you remove.)

I did a lot of internet based research on building out this frame, and saw one tiny comment from a consumer which has resonated with me lo these many past months….”The large frame build required considerable more fitting than the regular Glock 19 and 17 builds.” Boing. Yes I learned a lot, and would like to pass along some tools, tips and techniques I learned the hard way.

You can buy 80% frames in multiple colors compatible with 9mm Glock 17’s, 19’s, 26’s, 10mm 20’s, .45 ACP 21’s and even the tiny 9mm 6+1 Glock 43 (practice build something else first-not much room for mistakes working inside those tiny G43 frames.) Despite all my trials and suffering, I still recommend the Polymer80 brand people in selecting a frame kit. Their product is extremely well made, and their Customer Service department is top notch. They treat you like a friend and even gave me an old Native American Nickname “Ohitsyouagain” which they said means “Mighty Builder!”

In addition to finishing off the frame, you need Glock type parts to fill the lower receiver, a slide, barrel and parts to fill the upper receiver generally associated with Generation 3 Glocks. Not Gen 4. Not Gen 5.  I took my time getting the mailman to deliver a trickle of parts from internet bargain parts sales hopefully under my wife’s Financial Threat Look-Down Radar. The slide and barrel were the biggest purchases and some of the bargain priced items were no bargain at all.

What I can now firmly recommend, is if it is your first time build and you are getting your frame from Polymer80, then get your parts kits directly from Polymer80, or get original (OEM) Glock parts from someone like Brownells. If you want to fancy up a slide, barrel or trigger you can do it later or on a subsequent build. I was sad to learn a lot of aftermarket Glock parts are being sold out of spec. Took me a while to learn that one, and a quite a few more dollars reordering a bunch of original Glock parts.

There are a ton of online resources which will help you see what the building process looks like before you start cutting, grinding, drilling or sanding, and my absolute favorite turned out to be a guy several half hour videos called “The Marine Gun Builder.” He shows every step from getting the tabs off, the recoil spring channel cut out and the holes drilled so you don’t have to do it alone.

He highly suggested using a Dremel tool for several steps (even for drilling the holes instead of using a hand drill or drill press) and advocates getting a flexible shaft adapter for your Dremel. It clamps into the Dremel and allows you to grip the grinding/drilling end like a pencil and I found it very useful in the finishing process. I bought one of the flexible shaft things off of Amazon for $12. A bit of sandpaper was also handy in the 220, 300 and 2000 varieties for smoothing out the polymer.

Cutting out a U-shaped tab from the recoil spring and guide rod area, was pretty easy using the Marine Gun Builder advice to clip the tab in an X and then grinding the rest of it smooth. The Polymer80 people include a large drill bit for you to use at this step, but I found it to be none too elegant, and easy to grind too much polymer plastic even at low drill speed. Take the slow and easy way. Every time you want to add a power tool back away and reconsider if just using a hand file or sandpaper would suffice.

How hard could it be to drill three holes in the frame while clamped into the jig? Turned out it was hard for me. Much harder than anticipated. You can even drill crooked while using pilot holes.  Ah well, thanks to the internet “How to fix your Polymer80 holes” it turns out you can fill them with JB Weld QuikWeld and start over again. (Thank you again Amazon Prime for delivering JB Weld to me for $5.27 in less than 24 hours in these Stay At Home Order Days instead of me wandering into Home Depot for glue and Corona Virus exposure.)

Once you have your frame prepared, install your Glock parts and be prepared to sand some hole facings or true up your drill holes. It happens. Use sandpaper or hand turned drill bits-not power tools.  Once again the internet is your friend showing you how to install every Glock part in the receiver and slide.

One of my initial questions about building an 80% pistol from scratch was quickly answered “Can I build a Glock pistol from parts cheaper than just buying it off the shelf?” The answer was no.

All told, the assembled parts come out to just about exactly what I would have paid for a similar factory assembled Glock.  In the G19 and G17 builds you might get parts cheaper than I did for the large frame G20 build, but all in all it comes out about the same, and home builders seem to be stuffing the 9mm builds full of upgraded slides, barrels and trigger parts, all of which cost more money than factory stock.

But you do learn a lot, have some pride in the building process and have a resulting base firearm you can upgrade with more or better parts like a hot rod car.  Oh, and the lack of serial number, government involvement and registration….yeah, I like that part too.