A device for controlling the firing of a paint ball gun includes a shell having a muzzle, a ball inlet, and a gas inlet, forward, intermediate and rear ports, and a main line; a reciprocating member communicating with the main line; a sleeve assembly comprising forward and rearward sleeves releasably secured together, the rearward sleeve comprising peripherally arranged inlet ports, a peripheral first port communicating with the rear port, and a peripheral second port communicating with the intermediate port; a plunger slidably disposed in the forward sleeve and comprising a first peripheral space defined between the plunger and the forward sleeve; a retaining sleeve in the rearward sleeve and extending into the plunger; a sliding valve in the retaining sleeve, the sliding valve comprising a transverse passageway; a cylindrical block comprising a transverse passageway; and a hollow retaining member releasably secured to both the rearward sleeve and the block.