Rugged Suppressors Piston, 1/2x28 (Obsidian 9)

Tilting-barrel pistols need a recoil booster, also called a Nielsen device or piston, to cycle reliably when a suppressor is hanging off the muzzle. The added mass of the can slows the barrel's rearward travel enough to short-stroke the action; the booster uses a spring-loaded piston to give the barrel an extra impulse off the suppressor body so the slide unlocks and cycles normally. The Rugged Suppressors Piston is that part for the Obsidian 9, machined from 17-4 stainless steel for durability under repeated 9mm impulse.

This is the OP009 variant, threaded 1/2x28, which is the standard 9mm pistol thread pitch. It fits the Glock 43, the Sig P938, and any 9mm pistol with a 1/2x28 threaded barrel. The piston threads directly onto the host barrel and seats inside the Obsidian 9's spring-loaded booster assembly, so when you change hosts to a barrel with a different thread pitch you swap to the matching piston rather than buying a new mount.

Rugged offers the piston in several thread pitches across the Obsidian 9 and Obsidian 45 lines, so verify your host barrel's thread pitch before ordering. For a fixed-barrel host such as a PCC or a non-tilting pistol, you run a fixed-barrel spacer instead of the spring-loaded piston; the piston is specifically for tilting-barrel pistols that need the booster to function.