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GEMTECH's GMT-300BLK suppressor utilizes our patented G-Core technology. 300Blackout is a unique round that super and subsonic ammunition function differently in the same rifle. The suppressor is optimized for use with both super and subsonic ammunition in short barreled rifles. The GMT-300BLK, being a G-Core suppressor, is completely user serviceable.

The G-Core® design began its life as a simple hand drawing from one of our engineer's brainstorming sessions in the summer of 2013. The idea for a solid two piece design was not something new in the world of suppressors; however the unique use of turbulence voids had some merit. We began modeling this design in computational fluid dynamic software, which engineers just intuitively know how to use. The design proved strong and durable in the program so to maximize the strength and weight properties we used another program called Finite Element Analysis. It looked even more promising. The engineers had the shop guys crank out a couple of prototypes and then we shot them, a lot, frequently. Probably in ways we weren't supposed to. We didn't break them, we rejoiced. After our success we all had a meeting to discuss what to name this masterpiece of silencing goodness. After heavy debate, we came up with the name G-Core®.


  • The G-Core® was designed using the latest Computational Fluid Dynamics (CFD) software. The CFD software allows us to digitally engineer and test each design before building samples.
  • Using a combined total of over 60 years of suppressor design and innovation, the G-Core® was optimized for sound reduction and accuracy.
  • Finite Element Analysis (FEA) software was then used to analyze the G-Core® to ensure that it was both durable and light weight.
  • Each G-Core® model was subjected to the CFD and FEA software to confirm that they met all of the weight, durability, and strength requirements that our customers demand.
  • Rigorous live fire testing was conducted for each model until destruction.

These silencers are all the new black models.  Nothing has changed except the color.

What are the Critics Saying?


Specification Information

Caliber Rating .300 BLK
Thread Pitch 5/8x24
Color Black
Length 6.7"
Diameter 1.5"
Weight 13.9 oz
Manufacturer Gemtech
Build Material Titanium

5 Reviews For GEMTECH GMT-300BLK

  • Alpheus1/21/2017

    Good noise suppression. Unfortunately, similar issues. I started using Teflon tape on the cover threads. Used one layer first time and it disappeared after 40 rounds. I used a double layer of Teflon tape second time and ran 75 rounds of subsonic. I could remove the cover just using my hand. Also really need to clean the inside of the tube after shooting. I waited till third range trip and had to soak in CLP to finally remove the buildup inside the tube.

  • Pete11/23/2016

    I have put about 500 rounds thru the GMT-300 so far (mostly subsonic). Very effective sound reduction with subsonic. I agree with previous reviewers on the issue of clogged threads. I soaked overnight in Kroil oil the first time it locked up (effective but unreasonable to do every time). GemTech could have designed better!

    Talked with GemTech rep / recommends using a copper based anti-seize on the rear threads of the core/tube to make disassembly easier, as well as tightening the core to the barrel first, then putting the tube on over the core, which should keep from allowing the tube to get locked on to the core during tightening. I plan to try the anti-seize approach next.

  • HarryA11/14/2016

    While the GMT-300BLK is a pretty good suppressor, I'm a bit disappointed in the "pop" of the first round. Subsequent rounds are quieter. My greatest disappointment, however, is with the design of the screw-on cover. I've fought with it since I got this suppressor, and it's just getting worse. Now, in fact, I cannot remove the cover from the monocore assembly. I've used lubricants, vises, wrenches, impact drivers, etc., and still cannot budge the screw-on outer cover from the monocore. The depth of the socket receiver GemTech designed into the cover is laughably shallow; if the socket would fit into the front of the cover more than 1/8", you might be able to break the cover free using a breaker bar. I've contacted GemTech to inquire about the problem and have yet to receive a response.

  • Shooter4/30/2016

    Gemtech should update the socket insert for the owners at no cost. Not sure why they didn't design the insert to fully accept the depth of a socket. The end of the can just strips and ends up looking like shit. Get rid of the cute Gemtech trademark and engineer a solid and functional part.

  • Richard1/17/2016

    The GMT-300BLK is a well made suppressor, and does a very good job of silencing the round. That's as far as it goes. The internals foul very quickly. If you don't remove the outer cylinder every ten rounds or so, it is extremely difficult to remove, to the point that even a regular socket wrench won't do it. I must place the suppressor in a vise and use a cordless impact driver to get enough energy to break the can apart. When I do, the square drive opening in the end is so shallow that it begins to strip out. I have used various lubricants to try to make the job easier, with no success. So now I thoroughly tighten the monocore to the barrel using my socket wrench, then screw the cover on by hand, making sure not to tighten much at all. Even so, I loosen the cover every ten rounds and twist back and forth to break free any buildup. I think Gemtech could have done much better with their design

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The suppressor is optimized for use with both super and subsonic ammunition in short barreled rifles chambered for the 300Blk round only.

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