A gas generator (10) is provided including a housing (12). A gas generating composition (16) produces expanded gases upon activation of the inflator (10), thereby increasing the internal pressure and compressing the spring (50) operably coupled to the gas release member (40). As the spring (50) is compressed, at least one gas exit aperture (44), sealed prior to gas generator (10) activation, is opened as the gas release member (40) slidably engages an inner wall (11) of the housing (12). After gas generator (10) activation, the spring energy of the spring (50) gradually equalizes and then exceeds the gas pressure of the system gases, thereby once again attenuating the gas exit opening to maintain an optimum average system pressure as the gas is released from the housing (12).