The SilencerCo AC25 Osprey/Octane Piston is a durable, easily interchangeable component crafted from 174 stainless steel and heat-treated for maximum longevity, designed to adapt pistons to different host firearms and calibers while maintaining reliable semi-automatic cycling through the Nielson device that unlocks pistol barrels. This stainless steel piston features a 1/2"-28 thread pattern compatible with SilencerCo threaded barrels and offers female threading for secure attachment, with the option to add a Fixed Barrel Spacer for fixed-barrel applications to ensure proper alignment and performance. XL pistons are available for firearms requiring extra length between the threaded barrel and the silencer, enhancing reliability and timing across a variety of setups. The AC25 is designed to work seamlessly with SilencerCos Osprey and Octane series, as well as other compatible platforms, delivering consistent piston timing and durable operation in demanding shooting environments. Ideal for shooters seeking versatile, fast-to-change piston solutions without compromising durability or performance, this piston supports easy caliber and host firearm adaptation while preserving smooth, reliable cycling in 9mm applications.