Blowback Armory - The Airsoft & Gas Blowback Rifle Specialist

The RA Tech NPAS (Negative Pressure Air System) is essentially an adjustable proportioning valve that is installed in the nozzle of any WE Open Chamber rifle or Tokyo Marui pistol for FPS adjustment. This upgrade works by changing the amount of gas or air pressure that goes to firing the bb. The portion of gas or air pressure taken away from actually firing the bb is dispersed into the blowback chamber. The effect is an adjustment in the FPS (adjustable via provided tool), allowing higher or lower than stock fps, depending on adjustment.

Some air-smithing may be required to allow for an optimum fps adjustment range. Essentially what you have to do on most platforms is take material off of the crown seat in the blowback portion of the nozzle, being careful not to take off too much material as an air passage still must be present for gas to escape behind the NPAS into the blowback chamber, completing the gas cycle.

You can also have us do it by purchasing our repair center option and sending your gun in to us. We guarantee optimum FPS adjustment range when we install it.