The characteristic of one or more of the gas springs themselves used in a revolver cannon or breech cannon is adjusted while the system is in operation. This is done by a separate, self-contained system, which can adjust the gas spring from hard to soft, for example, and back to harder/hard and can thus adjust the characteristic of the gas spring without the loss of gas. In the simplest embodiment, this system has two additional elements, preferably a reserve tank and a connecting line that connects the reserve tank to the gas spring via a valve.