Gas system of a firearm

A firearm comprising a barrel comprising a gas opening, and a gas system, in which the gas system comprises a gas block, a gas piston, a force transmitter assembly comprising at least one force transmitter, an indexing part, gas openings, in which the gas block is fixedly attached to the barrel, in which the gas piston is positioned by the indexing part, in which the gas system gas is configured to pass through the gas opening of the barrel via the gas openings of the gas system into the gas block and to set the gas piston to movement, wherein the gas piston is connected via a spring-loaded pin or bushing to at least one force transmitter of the force transmitter assembly, such that in the gas system the gas piston during its movement backwards is configured to close the gas opening of the barrel for a defined time period and that the gas piston is not transmitting power/energy from combustion gas to the force transmitter assembly unless the gas openings of the gas system are closed.