Pressure-relief system for gun fired cannon cartridges

In a cartridge munition comprising a cartridge shell and a projectile inserted into the cartridge shell and mechanically connected to the cartridge shall, herein a pyrotechnic propulsive charge is locate in a propulsion chamber of the cartridge shell that is ignited by means of a pyrotechnic igniter, and whose propulsive gases exert a force on the base of the projectile when they burn, by means of which the projectile is driven out of the cartridge shell when the munition is chambered in a gun barrel, and wherein least one passage exits from the propulsion chamber through the cartridge shell that is substantially filled with a fusible, solid, pressure-tight material whose melting temperature is lower than the ignition temperatures of the pyrotechnic igniter and the propulsive charge of the projectile, the improvement wherein at least one non-fusible, rupturable member is positioned and forms a flat face between the fusible solid material and the propulsive charge in the propulsion chamber, and wherein a non-fusible plug is disposed in the passage containing the fusible material on the side opposite to the rupturable member, said rupturable member and said fusible solid material together having sufficient strength to withstand operating pressures within the propulsion chamber when the projectile is fired out of the cartridge shell, said rupturable material being configured to rupture and release gases from said propulsion chamber when said fusible material has melted and upon ignition of said propulsive charge when the munition is not chambered.