Patent ID: 8250964
Filing Date: 2012-08-28
Classification: F41A

Abstract:
1. A firearm having a gas operating system, comprising: a barrel having a cartridge chamber and bore; a gas expansion housing located adjacent the barrel; a chamber located along the gas expansion housing and in flow communication with the bore of the barrel; a gas flow metering piston received along the chamber of the gas expansion housing and including a piston body having a first end and a second end, the metering piston moveable between a first position along the chamber wherein a flow of gas can pass from the barrel bore into the chamber of the gas expansion housing, and a second position wherein the piston defines an obstruction of the flow of gas from the barrel bore into the chamber of the gas expansion housing for regulating the incoming flow of gas received in the chamber of the gas expansion housing from the barrel bore; wherein the piston further comprises at least one longitudinal groove formed along the piston body and defining a gas flow path therealong, the at least one longitudinal groove being formed in the piston body in a substantially helical manner about a cylindrical axis of the piston.