Our pistons were designed to be easily changed for different host firearms or calibers. Pistons are built with 174 stainless steel, then heat-treated for maximum durability. The piston is part of the Nielson device that moves and allows semi-automatic cycling for unlocking pistol barrels. Throw a Fixed Barrel Spacer on for fixed barrel applications.
XL pistons are for firearms where the silencer requires additional length between the threaded barrel and the silencer.