Silencer Co AC31 Piston | 9/16×24 | .40 S&W

The Silencer Co AC31 piston provides the threaded interface between Silencer Co Osprey and Octane family suppressors and compatible .40 S&W pistols. It is manufactured from 17-4 stainless steel and heat-treated for enhanced durability. The piston contains the female threads used by the Nielsen-style device to permit semi-automatic cycling on compatible host pistols. This part is intended to be changed when adapting a suppressor to a different host or subcaliber; use a Fixed Barrel Spacer for fixed-barrel applications.

Common applications include precision range training and competition shooting where users switch suppressor hosts or subcalibers.

Product Specifications

• The manufacturer is Silencer Co.
• The manufacturer part number is AC31.
• This piston fits the Osprey/Octane family of suppressors.
• The thread pattern is 9/16×24.
• The listed caliber compatibility is .40 S&W.
• The piston material is 17-4 stainless steel and it is heat-treated for durability.
• The finish is specified as Stainless.
• The product type is listed as Silencer Piston.
• The NFA thread pattern is 9/16×24.
• The series is identified as Piston 9/16×24.
• This piston is not designed to be disassembled.
• The overall length is 2.1 inches.
• The width is 1 inch and the height is 1 inch.
• The UPC is 817272010213.

This piston is a straightforward replacement part for shooters who need to adapt their Silencer Co Osprey or Octane suppressor to a .40 S&W host with 9/16×24 threading. Its stainless construction and heat treatment prioritize longevity and consistent fit, making it a practical choice for range-focused shooters and competitors who change host firearms or subcalibers.