Abstract: A paintball gun anti-blocking device includes a first, infra-red receiver and emitter disposed near the bottom of the inner wall of the gun tube to detect when the paintball enters the normal shooting position. A second infra-red receiver and emitter are positioned relative to the trigger as to detect if the trigger is pressed to the shooting position.

Abstract: An Improvement in the structure of Paintball Gun means to put an additional O-ring onto the perimeter of the front distal end of the firing plunger in order to block off the reversing flow of compressed gas after firing and ejecting, and to enhance the stability of to-and-fro gliding smoothly of the firing plunger as well as to decrease the wearing and abrading of all O-rings on the firing plunger. Moreover it prolongs the service life of the firing plunger. Thus, it implements multiple purposes and effects aforesaid.