Building a Glock Part 1: Lower Assembly

Want to build your own Glock pistol? For people who like to build guns, AR-15 rifles are by far the easiest to customize. The AR-15 is a long-established platform and continues to be the standard for modern rifles, with a lot of parts and options available for a build.

In the handgun world, Glock has become the customizable equivalent to the AR-15. Before Glock, 1911s were at the top of this list. But now Glocks are even challenging Browning’s legendary 1911 for those who want to build their own handgun.

There are a ton of options from a wide variety of companies to choose from when building a Glock. In our four-part series, we will go through the steps of building a Glock pistol. Be warned though, building a gun is addicting and you will more than likely want to build more.

Glock 19 frame and parts kit
The lower parts kit for a Gen 3 Glock will include everything needed to finish the lower/frame.

Just like with the AR-15 rifle, the process of building the gun is divided into two main sections: the lower frame and upper slide assembly. The lower, or frame, is the part considered the “gun” and everything else is simply parts of the gun. The lower frame and slide are what give the gun the look you want, and the parts installed change the quality and customized look it will have.

A Glock can be built with OEM (Original Equipment Manufacturer) parts or high-end after-market parts. We will go through each step of assembling the lower parts on the frame before moving to the slide assembly.

Parts Needed

Because frames and parts are easier to get for Gen 3 Glocks, I am building mine based on the Gen 3 design. When selecting your frame, make sure it is compatible with Glock Gen 3 parts. If you want to build a different generation of Glock, there are some options, just not as many. I chose a Polymer 80 frame in grey. It has a black slide with serrations that show the barrel through the slide. I’m building a Glock 19 Gen 3. Once you have a slide and frame selected, you will need a lower parts kit, an upper parts kit, and a barrel. If your slide parts kit does not include sights, you will need a set of those too.

Some basic tools will be needed, too. This includes a set of punches, needle nose plyers, an armorer’s block, an armorer’s hammer, and a sight pusher to install the sights. We will go over the tools needed as we install each section of the build. It’s important to have the right tools when building a gun, but a Glock build does not require nearly as many custom tools as an AR-15. A basic punch and hammer set from Real Avid or Wheeler are almost everything needed. An armorer’s bench block is helpful but a piece of 2×4 with some holes drilled in it can work too.

Installing the Magazine Release

Parts Needed: Magazine catch spring, mag release, and frame.

Mag catch spring and mag release
Mag release and mag catch spring are the first parts to install in the frame.

The first part we will install on the Glock 19 frame is the magazine catch spring. Don’t be fooled by the name and look for a spring. Instead, the mag catch spring (see photo above) is a small metal pin that pushes on the magazine release because of the pressure that is placed on it after installation. Using needle nose plyers, push the spring into the hole in the middle of the mag well from the top. Push on the spring to make sure it is seated all the way. Next, insert the mag release from the right side of the gun.

Installing mag catch spring
Look down into the mag well and push the mag catch spring to the right. The spring will slide into a groove as you push.

The mag release must go behind the spring so you may have to use a pick or flathead screwdriver to pull it back so the mag release can slide in behind it. Now push the spring to the right side of the gun and into the groove (see photo above). I used a small flathead screwdriver to push the spring over. This will put pressure on the mag release.

Putting Together the Trigger Assembly

Parts Needed: Trigger housing, connecter, trigger spring, and trigger bar assembly.

The first thing we will install is the connector to the trigger housing. There is a longer piece that sticks out from the connector you push into a slot on the trigger housing (see photo A below). Next, the trigger spring will connect to the back of the housing. There is a hole for the spring to attach to (photo B below). Attach the other end of the spring to the trigger bar as shown in photo C and the trigger assembly will be ready to install in the frame. Install the trigger as well if the trigger bar does not already have the trigger attached. The kit I ordered included a trigger, but it was not installed on the trigger bar.

Trigger bar for Glock 19
Trigger assembly for the Gen 3 Glock 19. The trigger bar (bottom) is connected to the trigger by a single pin.

To attach the trigger, use the small pin and insert the trigger bar into the slot on the top of the trigger. A small armorer’s hammer works best for tapping in the pin. The photo above shows the trigger bar attached to the trigger. After installing the trigger assembly, we will move on to the slide stop, locking block, and slide catch/release. This will be in Part 2 and then we will move on to the (upper) slide parts kit. The slide assembly is easier than the lower parts kit, at least for me, and goes a little faster.

Trigger housing with connector.
Photo A: The connector pushes into a slot on the side of the trigger connector. The top of the trigger connector sticks out a little, but this is normal.
Trigger housing with connector.
Photo B: The trigger spring will attach to the hole in the trigger assembly. The connector, as shown above, will stick out form the trigger housing.
Connecting trigger spring to trigger bar
Photo C: Attaching the trigger spring to the trigger bar makes the trigger assembly ready to install in the frame.

Final Thoughts on the First Stage of Building a Glock 19

When building a gun, the most important thing to do is take your time and be patient. Guns can be frustrating and when you are in a hurry, it gets even worse. Small parts will not want to fit, springs will go flying across the room, or you won’t be able to find the right tools. I have had times when I stopped working on a gun because I didn’t have the right tool and learned the hard way not to “wing it” with something else. If you must put everything up and wait a few days for a tool to arrive, wait for the tool. Once you have every tool you need, you can work on the gun with more confidence knowing you are doing it right. I’ll see you tomorrow when we finish the frame assembly.

Sheriff Jason Mosher is a law enforcement generalist instructor as well as a firearms and tactical weapons trainer. Jason graduated from the FBI-LEEDA (Law Enforcement Executive Development Association) and serves as a Sheriff for his day job. When he’s not working, he’s on the range, eating steak, or watching Yellowstone.

Sign Up for Newsletter

Let us know what topics you would be interested:
© 2023 GunMag Warehouse. All Rights Reserved.
Copy link
Powered by Social Snap