Abstract: An automatic safety system is built into a pneumatic motor actuated dispensing gun to prevent the gun from dispensing liquid material whenever the nozzle of the gun is loosened or removed from the gun body. The safety system comprises an air flow passage contained internally of the gun body for connecting the pneumatic motor to a normally sealed surface located between the nozzle and the gun body. Removal or loosening of the nozzle relative to the body, breaks this sealed surface and results in leakage of sufficient air pressure to atmosphere as to prevent actuation of the pneumatic motor and thus opening of the normally closed flow control valve of the gun.