A removable gas supply for a weapon simulator, wherein the gas system
cycles the bolt or slide of the firearm to provide recoil, actuate a
hammer/trigger mechanism and provide realism of the original weapon
functions. The weapon simulator has a housing defining a piston chamber
and a piston positioned in said chamber and connected to the bolt. The
simulator also includes a valve chamber in the housing connected with
said regulated gas supply and said bolt, and a recoil valve positioned in
the valve chamber to control the release of gas from said regulated gas
supply to said piston chamber to generate recoil in the weapon simulator.