A gas density monitoring system for high voltage gas circuit breakers. The gas density monitoring system comprising a gas density device mounted directly on a circuit breaker tank end cover. When the gas density device is fully secured to the tank end cover, the gas density device works in conjunction with a self-sealing valve body to provide a self-sealing, direct pathway between the pressurized tank and a sensing element of the gas density device. This pathway permits the gas density device to sense the circuit breaker tank pressure via an angled port through the tank end cover that limits pressure transients that may result from the normal operation of the circuit breaker. The gas density device contact settings may be verified without removal of the density device from the gas circuit breaker or venting the enclosed gas inside the gas circuit breaker to the atmosphere.