(30 customer reviews)


A high-quality pistol frame in sleek black, offering versatility and customization for firearm enthusiasts.

GST-9 mod 1 first released in November 2019, the GST-9 frame (GST-9 build kit) V1 set a precedent for the 80% frame market. It provided a modular grip system while maintaining Gen 3 G19 parts compatibility. With 3 years of customer feedback and thousands of rounds down range, we’ve raised the bar again with the new GST 9 frame!

The gas pedal shape and location were revised and re-contoured for optimized controls during the recoil cycle. The grip system of buy gst-9 frame was redesigned to guarantee a flush fit with grip modules when building out your frame. Last but not least, the rear rails were split into a 2-piece system to greatly help streamline the assembly process of GST-9 build kit.


  • Modular frame gives you the possibility of a 19, 19X, 19L, & 17-size weapon system in a single 4-in-1 platform.

  • Compatible with Glock 19 Gen 3 parts, holsters, & aftermarket accessories.

  • Ergonomic: undercut trigger guard, high beavertail, glove bevel, scalloped mag release, no finger grooves, & curved gas pedals as standard.

  • Premium internal rail components extended 3X OEM length, made of stainless steel GST-9 build kit.

  • Easily ships to your door & completes in minutes.

  • Calibers: can be built out to support 9mm (G19) /.40cal (G23) /.357 Sig (G32).

*Please Note: GST-9 MOD1 frame only accepts G19 Gen 3 compatible internal parts and slides. See all possible build combinations here. Please refer to the instructional guide for assembly tips. Visit 80% Arms FAQ for common questions and troubleshooting tips.

**The MOD1 gst 9 frame does NOT accept Glock 17 slides. The MOD1 frame only accepts Glock 19, Glock 19L, & Glock 19XL slides* 

GST-9 build kit 80 Percent Arms strives to provide the highest level of customer service within 80% and the firearm industry as a whole. We support all of our products with a lifetime warranty* so you can build with confidence.


Due to ATF regulations, we cannot legally include the jig or frame rails with the buy gst-9 frame. The jig and MOD1 frame must be purchased as two separate items. Each jig includes one set of MOD1 frame rails. You will need to purchase one jig for every MOD1 frame you plan to build. Frame rails are ONLY included with the jig, not with the 80% lower itself.


80%, 76%, unfinished frames/receivers can’t be sold with ANY other products in the same order

By using this website to purchase and/or use this product, you affirm that:

  • Permanent resident or US citizen, nor have you renounced your citizenship.

  • Never been convicted of a felony.

  • Verified that you may possess, purchase, and use this product under all applicable city, county, state, and/or federal laws

  • You have never been convicted of a crime punishable by more than one year in prison.

  • Have never been convicted of a domestic violence crime misdemeanor.

  • You have never been committed to a mental institution or adjudicated as mentally defective.

  • Not currently under a court order restraining you from stalking, threatening, or harassing a child or an intimate partner.

  • Authorize Freedom Unlimited to send emails, text messages, or other forms of electronic communications to the contact information you provide.

GST-9 build kit – NOTES:

  • All GST-9 mod 1 80% Blanks can’t be combined with any other products. (You can combine the different style of Blanks ie compact + full size and/or corresponding tool/jig kit)

  • 80% GST-9 frame blanks will not come with any instructions, It is up to the buyer to do your own due diligence. If you are not mechanically inclined, do not purchase GST-9 frame.

  • We are not Lawyers, so Please check your local and state law. When in doubt, please do not purchase.

  • Please do your GST-9 mod 1 own due diligence and research before making a purchase. It is the CUSTOMER’s responsibility to know all applicable laws that apply. Freedom Unlimited Group Inc (FU INC) is not and will not be held responsible for any city, county, state, and/or federal laws that you (the purchaser) do not comply with. Due to the volatile nature and ever-changing laws regarding unfinished frames and lowers, these items are not returnable. Warranties will be handled on an individual basis.

DISCLAIMER: GST-9 mod 1 is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.


  1. Federick V.

    After I got my GST together, the slide appeared to lean to the right. I contacted the company and explained the issue, and was asked to send pictures. Upon reviewing the pictures, they took care of the issue, no questions asked! They were easy to work with, and the level of service I received was easily some of the best I’ve ever received!
    Read more about review stating Amazing customer service!
    I am a fan for life!!

  2. Xavier F.

    This thing rocks, easy to build, awesome grip, really well designed. The extension makes it into something special. I love the texture, saw some reviews that wanted more, I think it’s perfect. if you like a sig grip rounded vs the squarish glock grip you will really enjoy shooting this.

  3. Kyle X.

    I could not be happier for the Pistol Frame kit. The instructions and the Website videos made it so easy for a “first-timer”. Thanks again!

  4. gary o.

    nice looking and performs well

  5. William K.

    Honestly I hope this thing holds up, the fact that it fits in a glock holster is a huge plus. I’ve only gotten it out to the range twice but really hoping this this holds up because it’s definitely a winner in my book!!

  6. Carl W.

    Great frame and even better jig. I wouldn’t call myself a master builder but have done several p80 builds. This jig makes most of the tips and tricks I’ve learned along the way irrelevant due to the design. I am very impressed at the engineering that went into the jig; makes for a quality build. The bits provided are quality. The frame is awesome;Read more about review stating Great frame and even better
    quality polymer and molding. Couldn’t be happier. Order one knowing it will take some time to get, but its worth the wait. I have an fde frame and will be ordering other colors once production catches up. Couldn’t recommend more!!

  7. Wesley S.

    Completion was super easy, only took about 20 minutes. Feels very good in the hand and shoots well. Took about a year to get it and was worth the wait.

  8. Adams H.

    Bought this due to the versatility of the frame. I was impressed with the quality and the instructions were easy to follow. Very good grip. Everything I was looking for in a frame.

  9. Gideon N.

    I had purchased 2 polymer 80 kits prior to this – and they were terrible! Pin holes didn’t line up, the rails were too low and the slide hung up. Your GST-9 was a pleasure to put together, all the pin holes lined up, the rails were at a correct height , and It functions very well. I’ve had a couple friends who tried it and they loved the pistol!
    Would highly recommend it!

  10. Sam P.

    Love the way the grip is shaped. Unlike most glocks, it’s rounded and much more ergonomic. My first frame had problems with a drooping rail making the whole gun not even functional at all, but 80 percent arms was kind enough to replace the frame for me. Now the whole gun is actually functional and shoots reliably too.

  11. Rob T.

    Awesome little pistol

  12. Wilfred R.

    Awesome piece. I cannot find a problem on it.

  13. jude r.

    Of the several 80% Glock builds I’ve done, the GST-9 has been the most reliable. Undoubtedly the best jig out there, GST has a winner on their hands with this one.

  14. Peter L.

    Love the feel free the grip. I unfortunately am not in a position to complete the build yet.
    I am looking forward to it when I can.
    Thanks for a great product.

  15. Alfred S.

    Bought 2 kits. Completed zero. Parts appear very robust and higher caliber than competitor’s. Jig is certainly more robust and appears to be able to produce more accuracy.

  16. Kyle R.

    Easy easy easy. I can’t say more than that. The spots that need trimming, sanding, whatever, are easy to get to and it’s not hard to make it look good. Highly recommended for a fun project, especially if you’re doing this for the first time or introducing someone else to the fun that is DIY.

  17. Steven A.

    Really a Great Frame, and Yes! 5 Stars each for build, cost, function so I guess that’s actually 15 Stars.

  18. Martin B

    I got in on the pre order and waited for a long time. Frustrated, but it finally got here and was worth the wait. I have had it for several months now, and it is awesome. Feels right in my hand. Now, if you guys would make a CZ-75 shaped frame for the Glock, I would get in line again!

  19. Pat W.

    I was able to snag one of the Patriot brown frames. I love it so much. I got the comp grip for it and it is now perfect.

  20. Lambert A.

    I am a novice. I decided i wanted to know how a hand gun worked, so i figured the best way was to assemble one.
    When the frame came, and i received my trigger and slide, i started the process. Before i realized it, the frame was basically done. I was amazed that a novice like me, could put one together so quickly.

  21. Jeeson C

    So easy even a cave man can do it!

  22. David M

    GST-9 frames are so incredibly refreshing after building with P80 all the time. I like my P80’s but they’re incredibly bland when side by side with these frames. Still hoping to get a complete some day.

  23. Ben P.

    Very easy to complete.

  24. Bennett N.

    Came out great very happy with this

  25. Tom B.

    Awesome product thanks keep up the great work

  26. Charles

    Hands down the best 80% glock style frame on the market!

  27. Mathew

    Well made and easy to finish. Just waiting since Oct for my slide to finish it up. I see no issues with it. Size is what was I looking at to. Hopefully it will shoot as well as it goes together. Have no problems recommending. Even thinking of getting another.

  28. Jonathan H.

    Great feeling and handling lower build.

  29. Jona K.

    This was my third frame. Love the platform and versatility. Can’t wait for more colors and caliber options

  30. Nathan C.

    I’ve been playing, working with and putting different ideas on my own pistol configurations for several years now. 80% arms makes it easy to play around with this serious hobby. For those that want their build to be basic it’s the only way to go.

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