Gemtech GM-9 / Multimount 9mm Piston – 1/2x36
Not Yet Rated | Write the First Review SKU: 222-GEM-12170
UPC: 609729000000
MFG#: 12170

Gemtech GM-9 / Multimount 9mm Piston – 1/2x36

The Gemtech 9mm piston (1/2x36) keeps your GM-9 or Multimount 9 running on hosts that use the 1/2x36 thread pitch—most commonly AR-9 / PCC barrels and some aftermarket 9mm uppers. If you’re moving your Gemtech can between a pistol and a carbine, this piston is the clean, reliable way to match that 1/2x36 thread without janky adapters.

Precision-machined for alignment and durability, it drops in fast, maintains POI consistency, and handles high round counts without loosening up. Keep one installed on your carbine host and another in your range bag so swaps are instant.

Why this 1/2x36 piston

• Correct spec for AR-9/PCC – Matches common 1/2x36 9mm carbine barrels

• Direct fit – Built for Gemtech GM-9 and Multimount 9 booster housings

• Reliable alignment – Tight tolerances help protect threads and baffles

• Fast host changes – Tool-free swaps between 1/2x36 and other pistons

• Built to last – Hardened steel, wear-resistant finish

Compatibility

• Suppressors: Gemtech GM-9, Multimount 9 (Tundra LID users should select the matching piston for that system)

• Typical hosts: AR-9 / PCC, Colt-pattern and similar 9mm carbines using 1/2x36

• Note: Most factory 9mm pistols in the U.S. run 1/2x28; 1/2x36 is primarily a PCC thread. Pick your piston to match the barrel.

Specifications

• Thread pitch: 1/2x36 RH

• Caliber: 9mm

• Material: Precision-machined steel

• Finish: Black, wear-resistant coating

• Installation: Tool-free piston swap in Gemtech booster housing

Installation & use

Verify your barrel thread (1/2x36), clean/lightly lube the piston/booster, seat the spring and retainer per Gemtech’s manual, and hand-tighten. Function-check before live fire. For pistols with fixed barrels, use an appropriate fixed mount instead of a booster/piston.

FAQ

Is 1/2x36 the right thread for my 9mm?
If it’s an AR-9/PCC, likely yes. Most handguns use 1/2x28, so confirm your barrel marking before ordering.

Will this piston fit the GM-9 and Multimount 9?
Yes. It’s designed for both GM-9 and Multimount 9 booster housings.

Can I use this on a fixed-barrel host?
Use a fixed mount for fixed barrels. Pistons/boosters are intended for tilting-barrel pistols and will also be fine in many PCC setups, but follow manufacturer guidance.

How does this differ from the 1/2x28 piston?
Same function, different thread spec. Choose 1/2x36 for most AR-9/PCC barrels and 1/2x28 for most U.S. 9mm pistols.

Do I need tools to install it?
No. Piston swaps are tool-free; just follow the booster assembly steps and torque guidelines in Gemtech’s manual.

Why keep more than one piston?
If you run multiple hosts (PCC + pistol), dedicated pistons for each thread let you switch platforms quickly and keep threads clean.