Patent ID: 7905171

Claim:
A noise reducing piston for a firearm sound suppressor booster configured for use with a firearm having a barrel, the piston comprising: an elongated body defining a rear end, a forward end, a peripheral surface, and a longitudinal axis; a central bore through the body extending from the rear end to the forward end and sized to allow passage of a projectile fired from the barrel; internal threads adjacent the rear end of the body and configured to couple the body to the barrel; a plurality of elongate gas vents disposed forward of the internal threads and extending from the central bore to the peripheral surface, each gas vent being linear and elongated only in a direction parallel to the longitudinal axis of the body; and a plurality of indexing spokes disposed on the peripheral surface of the body forward of the gas vent and the gas vents permit expansion of gases accompanying discharge of the firearm into a space between the peripheral surface of the body and the sound suppressor, and wherein the internal threads are rotated for tightening in a first direction and side edges of the vents are angled in a corresponding direction such that expanding gases passing through the plurality of gas vents tends to rotate the body in the first direction and tighten the coupling between the body and the barrel of the firearm.