The world of do-it-yourself-gun-building has never been better. The 80% industry is fresh off a win against an anti-gun regulation, and building your own AR-15, Glock, SIG P320, or more is very, very possible. I’ve done it a time or two, and to celebrate the rule change, I built one more, specifically a Polymer80 Glock-pattern handgun of the compact variety. Polymer80 calls it the PF940C. It can be built as a 9mm Luger or .40 S&W, but since it’s not 2003, I avoided the .40 S&W and went with 9mm.
The Polymer80 PF940C kits use a polymer frame that’s pretty easy to mill. The process to take it from an 80% frame to a complete gun only requires basic hand tools, specifically a drill or Dremel. In fact, these are so easy to build that a guy I follow on social media built one without power tools. The PF940C uses Gen 3 Glock parts and allows you to utilize the massive Glock aftermarket to complete your build.
Building the Polymer80 to 100%
The Polymer80 frames come with a simple jig and a couple of bits for your drill. Your task is to remove some polymer to make everything fit. Before you do anything, you’re supposed to toss it in the jig, and the instructions will show you exactly which parts to mill.
I always start with the barrel block. A Dremel makes short work of the barrel block, and you can cut out the majority of the barrel block with the Dremel. After that, a little trimming with a sharp knife can be done. A Dremel can do the whole thing, but I tend to be cautious.
After that, you have to remove a set of polymer rails above the trigger guard and at the rear of the grip. These need to be cut out, and you’ll likely have to use a file or a bit of sandpaper to smooth things over. Finally, you’ll need to drill three holes, two up front and one in the back. This is the hardest part of the whole operation.
If your holes aren’t centered, this can cause the hole to be too large, and if it’s too large, the gun will fail, and your frame will be basically useless. So don’t do that. Be cautious and slow, and take your time. Make sure the bit is centered and hit the drill fast rather than slow.
Why Build Your Own?
There are lots of reasons. It’s fun, interesting, and challenging. All of those are enough of a reason to give it a spin. There is something about finishing a gun and getting it to fire and function properly. A lot of times, you have to cycle the slide a few hundred times before it glides correctly. Even when it feels smooth, the gun might still malfunction. You’ll work that slide enough that you’ll have tennis elbow.
The Polymer80 frames have better overall ergonomics than the standard Glock pistol frame. The texture is better and more aggressive. The grip angle is more American than European—it’s more 1911-like. The grip angle isn’t a big deal for me, but it’s worth noting. The trigger guard has a super aggressive undercut that allows for a nice high grip on the gun. It allows for a more comfortable high grip than the standard Glock frame.
The rear of the grip features an overhand that also encourages a high grip and prevents slide bite. Glocks give me slide bite and I’m not a fan. Up front, the gun has a true Picatinny rail rather than the Glock-type rail. The differences are significant and, to me, worth it.
The downside is that you’re stuck with Gen 3 Glock parts. There are plenty of them, but you might want to get an extended magazine release because the Glock Gen 3 isn’t exactly great. There is no Glock Performance Trigger, and lots of the newer, better parts are also off the table. Luckily, optics-ready Gen 3 slides are plenty common.
Blasting Away With Your Polymer80
Let’s talk reliability. Reliability will depend on how well you did arts and crafts on your frame. If you do it right, the gun will function flawlessly—well, mostly flawlessly. There will likely be a break-in period where it will fire a few rounds, jam, fire a few rounds, and jam again. The number of rounds fired will likely increase between jams until it just stops happening. One of the best pieces of advice I have is to use Glock OEM magazines or Magpul Glock mags.
You don’t want to skimp on your magazines. With that out of the way, how well does the PF940C operate? Surprisingly well. I really love how the ergonomics function and how high of a grip I can get on the gun. One small surprise is the length of the grip, which has been extended slightly. This doesn’t cause issues with 15-round magazines but does prevent the bottom of my hand from pinning the magazine in when it comes time to reload.
With a stock Glock 19 on occasion, my magazine gets pinned during reloads. It’s the problem with my 2XL hands. The PF940C fits almost perfectly in those hands. The higher grip I have on the gun results in more control and the ability to either get the sights back on target or to keep those sights on target between shots. The front sight is easy to follow and easy to track between shots.
Things like accuracy will depend a bit more on your slide, barrel, sights, and skill. With my setup and the cheap Brownells slide, I found the gun to be pretty darn accurate. It’s easy to throw lead where I want it and keep up with the stock Glock 19 without much complaint or compromise. The PF940C can operate and function quite well. In fact, it can, if properly built, keep up with factory Glocks.
Carrying a Homemade Gun
I’m not sure if I would carry this gun or use it for defensive shooting. For one, I don’t trust myself to make a gun that works as well as a factory-made gun. I’m no gunsmith. At best, I’m a tier 1 Bubba with a Dremel. I don’t need a serious firearm fail when I need it most.
There is also admittedly some taboo to carrying a gun without a serial number. It’s not illegal to carry it, it’s not illegal to build a gun, and homemade guns do not need serial numbers. It might raise more questions than it’s worth; of course, you could serialize it. I do like building these guns, and I think a P320 is my next go-to. Does anyone else like to take a Dremel to a frame and call themselves a gunsmith? Or is it gunsmiff?
