The GST-9 V1 became a standard for the market for 80% frames when it was first released in November 2019. It offered a modular grip system while still being compatible with Gen 3 G19 parts. With the new GST-9 MOD1 frame, we've lifted the bar once again after three years of customer input and thousands of rounds fired!

For improved controls throughout the recoil cycle, the gas pedal's shape and placement were altered. When building out your frame, the grip system was overhauled to ensure a flush fit with grip modules. Last but not least, to substantially facilitate construction, the rear rails were divided into a 2-piece system.


  1.  A modular frame allows you to use a single 4-in-1 platform to hold weapon systems that are 19, 19X, 19L, and 17 sizes.
  2. Compatible with aftermarket parts, holsters, and accessories for the Glock 19 third generation.
  3.  Only the GST-9 is the first and sole 80% lower that works with Glock holsters.
  4. An undercut trigger guard, a high beavertail, a glove bevel, a scalloped magazine release, no finger grooves, and typical 45-degree gas pedals are among the ergonomic characteristics.
  5. Extend internal rails three times with premium stainless steel components.
  6. easily delivered to your door and finished in a few minutes
  7. Calibers - can support 9mm (G19),.40cal (G23), and.357 Sig (G32) bullets.

We are unable to legally provide the jig or frame rails with the MOD1 frame due to ATF rules. It is necessary to buy the jig and MOD1 frame separately. A single set of MOD1 frame rails is included with each jig. For each MOD1 frame you intend to make, you must buy a jig. Only the jig comes with frame rails; the 80% lower is not included.

What is the GST-9 frame compatible with?

The GST-9 frame is a modular polymer 80% pistol frame system compatible with Glock® 19 Gen 1-3 platform components. It is the world’s first truly modular polymer 80% pistol frame system. The GST-9 frame accepts any Gen 1-3 Glock 19 components, accessories, and holsters. This makes the GST-9 the first and only 80% lower that fits in standard Glock holsters.

What is the price of GST-9?

According to American Handgunner, the GST-9 pistol kit, including the frame, grip extension, completed RMR-cut slide, GLOCK OEM parts kit and Lone Wolf AlphaWolf fluted barrel can be purchased for $799.
You can as well get it from at $599 saving up to $200!

Will a GST-9 fit in a Glock 19 holster?

According to GunsAmerica Digest, the GST-9 frame accepts any Gen 1-3 Glock 19 components, accessories, and holsters. This makes the GST-9 the first and only 80% lower that fits in standard Glock holsters¹. So it should fit in a Glock 19 holster.

What parts do you need for GST-9?

According to 80% Arms, every GST-9 Pistol comes with the GST-9 Modular Frame, GST-9 Grip Extension - Full Size, The Wraith RMR Cut Slide - Completed Black, Straight-Fluted, Match-Grade G19 Barrel and GST9 Lower Parts Kit.

What magazine does the GST-9 use?

According to 80% Arms, the GST-9 is compatible with both Glock® 17 and Glock® 19 magazines. You can conveniently order these magazines from the comfort of your home by visiting, your number One Online Store for Firearm Accessories.

Why is my GST-9 slide not locking back?

There could be several reasons why your GST-9 slide is not locking back. One reason could be that the slide stop is not engaging the slide lock notch on the slide. Another reason could be that the magazine follower is not pushing up on the slide stop.

You can try to check if the slide stop is functioning properly and if the magazine follower is pushing up on the slide stop. If you are still having issues, you may want to contact 5D Tactical Sellers support for further assistance.