All our Valves right from the first one in 1994 has been what we call Volumetric IE the Power curve of the Rifle is controlled by the combination of the Cylinder pressure, the amount of air contained within the valve unit at the point of firing and opening time of the valve. All rifles using this system are quieter and have the sound of a crisp short crack at the muzzle when fired as there is no air wasted by the hammer rebounding. Which keeps the muzzle noise at a minimum as only the right amount of air is supplied into the breach at the optimum time. We work on the theory that if we don't put the noise in we do not need to take it out with excessive silencers on the muzzle. Also note the buffer to cushion the hammer noise. This is only one form of this valve and we can adapt it to suit all power levels and a full range of rifle shapes and sizes. Please contact us for more details.