JK Armament 155 Piston 9mm Luger 1/2x28 Stainless Steel

The JK Armament 155 Piston is a precision-machined replacement piston mount for the JK 155 series of suppressors, engineered to deliver reliable semi-automatic cycling on 9mm Luger centerfire pistols. Cut from 17-4 PH stainless steel, the piston is built for the rigors of repeated fire and easy field service.

The piston uses trapped gas pressure to oppose slide motion, keeping the suppressor seated on the muzzle during the firing cycle and releasing cleanly as the action unlocks. This makes the 155 Piston ideal for hosts with short dwell and brief reset, including 9mm Luger pistols and other centerfire pistol platforms that share the same 1/2x28 thread pattern.

Whether reconfiguring a JK 155 for a new pistol barrel or replacing a worn piston, this direct-fit stainless steel mount keeps the 155 series running quietly and reliably. The raw stainless finish is durable, corrosion-resistant, and easy to maintain.