GEMTECH'S Old School GM-9 Delivers Excellent Results

While it May be Old, It's Still a Cool Can

February 11, 2025 By Patrick Sweeney

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The Gemtech GM-9 was made to be light. Constructed mostly of aluminum, it uses steel in the threads, booster, and spring. From the outside it looks like any other 9mm suppressor, but it can be used with .300 Blackout in subsonic loads. It is not full-auto rated. Not that many of us have that option, and not going full-auto-rated is a small price for the light weight.

On the back end is the booster assembly. To remove the booster as a unit from the GM-9, grab (or use a strap wrench) the section with the round-ended grooves machined into the outer wall of the assembly. If you want to take the booster apart (say, to put in a fixed spaced for use on a PCC) then you need to unscrew the knurled and ridged disc at the rear of the booster assembly. Then swap the spring for your fixed spacer. Or just go with simple threaded rear cap. The GM-9 is compatible with the various Multimount adapters that Gemtech designed and offered over the years. This means you can go with a fixed thread rear (or as mentioned, a fixed spacer in the booster, replacing the spring) or the three-lug MP5 mount that were so hot an item for years they might as well have been made of unobtainium.

GM-9 piston or booster removed from suppressor — The booster is a separate assembly, which you can remove and replace with one of the Mulitmount rears, to use as a fixed-thread or three-lug mount. (Photo Provided by Author)

To disassemble the GM-9 to expose the baffles, you unscrew the cylindrical section with the sixteen flats on it. This is the part of the GM-9 that is the monocore. The front cap? There isn’t one, at least, not one you can remove, as it is an integral part of the monocore. That makes manufacturing a bit easier, and it also makes your life easier if you have an “oops.” As in, a baffle strike. If you have such a problem, the monocore is not the suppressor. Since the exterior tube is the part with the serial number, it is the suppressor. So, you can send your damaged monocore back to Gemtech with apologies for repairs without needing to file a transfer form. Just let them know it is coming, and keep the serialed part in your safe, awaiting the replacement monocore’s return.

Utilizing one of the Multimount rear caps, you can park the GM-9 on a pistol, a PCC, or even rifles in appropriate calibers. The GM-9 can be used with .300 Blackout in subsonic loadings, but you will need the appropriate-thread rear cap to attach it. The best part is that you can, with the correct thread rear, also use the GM-9 on lesser cartridges. Like .22LR. Will it be the quietest rimfire suppressor ever made? Maybe, maybe not, but then again it will be really quiet. The clearance for a 9mm bullet may be large down the bore for the .22LR, but the internal volume of the GM-9 far surpasses any rimfire suppressor made.

Gm-9 suppressor mono core baffles removed from cover. — The outer tube unscrews from the monocore, and since the tube is the serial numbered part, any work needing to be done to the monocore does not involve serial number paperwork. (Photo Provided by Author)

And since the GM-9 can be disassembled, and you’ll be taking it apart to clean it regardless of the caliber ammunition you use, then knock yourself out with rimfire. Your ultrasonic cleaner will make short work of the buildup. I mentioned strap wrenches. Well, pistol ammo is grubby. Rimfire ammo is incredibly grubby. You will be cleaning your GM-9, but if you shoot a bit too much ammo for hand-disassembly, you’re going to need a pair of plastic strap wrenches to wrestle it apart. The carbon and lead buildup does a remarkable job of locking things together. That’s just the nature of running a handgun-caliber suppressor.

As part of the Gemtech G-Core line, (the GM-22, GM-9 and GM-45) the GM-9 was replaced as the 9mm suppressor in the lineup by the modular Lunar 9 a few years ago, but that doesn’t mean the GM-9 is obsolete or ineffective. It still works fine, it still offers a great level of performance at a not-great price. If you find your local gun shop has one on hand, you would be well-served by picking that one up.