Silencer Co | Piston 1/2×28 XL | AC59

The Silencer Co Piston 1/2×28 XL (AC59) is a replaceable piston designed for the Osprey and Octane family of suppressors. It is manufactured from 17-4 stainless steel and heat-treated for durability, and provides the female threading that attaches the suppressor to a compatible host firearm. The piston functions as part of the Nielsen device to allow reliable semi-automatic cycling, and the XL length provides additional spacing between the threaded barrel and the suppressor. This piston is intended for use with 9mm hosts that use a 1/2×28 thread pitch.

Product Specifications

• The finish is Stainless.
• The material is 17-4 stainless steel and it is heat-treated for durability.
• The model fits Osprey/Octane suppressors.
• The listed size/caliber is 9mm.
• The thread pattern is 1/2×28 XL for extended-length applications.
• The NFA thread pattern is 1/2×28.
• The product type is Silencer Piston.
• The fit is specified as Osprey/Octane.
• The series is listed as Piston .5x28XL.
• An additional feature is Extended length.
• Additional thread compatibility is noted for Colt, RRA, Bushmaster.
• The item can be disassembled: False.
• The listed weight is 0.105.
• The UPC is 817272010237.

Constructed for interchangeability and long-term service life, the AC59 XL piston is a practical component for shooters running Osprey or Octane suppressors on 9mm hosts. Its extended profile accommodates setups that need additional spacing while preserving the Nielsen device’s function; suitable for dedicated range use and competition shooting where reliability and modularity matter.