SilencerCo AC626 Piston | 17-4 Stainless | 13.5×1 LHM XL

The SilencerCo AC626 piston is a service component designed to adapt SilencerCo suppressors to various host firearms and sub-caliber configurations. Constructed from 17-4 stainless steel and heat-treated for increased durability, the piston contains the female threads that interface with SilencerCo threaded barrels and is part of the Nielsen device that enables semi-automatic cycling on compatible pistols. For fixed-barrel applications a Fixed Barrel Spacer can be used to achieve the proper fit and function. This XL-size piston is intended for multi-caliber use across SilencerCo product families.

Product Specifications

• The manufacturer part number is AC626.
• The piston is made from 17-4 stainless steel and is heat-treated for durability.
• The listed thread pattern is 13.5×1 LHM XL.
• The NFA thread pattern is listed as 13.5x1mm LH in supplier attributes.
• The product type is listed as Multi-Caliber.
• The model designation provided is Piston.
• The finish is listed as Stainless.
• The listed size is XL.
• The unit is described as a silencer piston that contains female threads to attach to SilencerCo threaded barrels.
• The piston is compatible with Osprey Series, Octane Series, Omega K Series, Hybrid 46 (and specified Hybrid/Omega variants with Charlie piston mounts where noted).
• The product is intended to enable multi-caliber and sub-caliber host configurations for applicable SilencerCo suppressors, enabling semi-automatic cycling where the Nielsen device is used.
• The listing includes a weight value of 0.1 as provided by the supplier (units not specified by source).
• The UPC is 817272011623.

This AC626 piston is a straightforward service and conversion part designed for shooters who need a durable, interchangeable threaded interface for SilencerCo suppressors. It supports multi-caliber use and routine maintenance or host changes without altering the suppressor core, providing a practical option for range use, competition pistol setups, or armorer-level servicing.