A pyrotechnic inflator assembly comprising: a shell member having an inner surface , an outer surface , an open first end and a closed second end opposite the first end ; an end cap joinable with the shell member to at least in part enclose the open first end of the shell member to form an inflator subassembly , the inflator subassembly containing a quantity of pyrotechnic material and at least in part defining a combustion chamber wherein at least a portion of the quantity of pyrotechnic material is reactable to form product gas for inflation of an associated airbag cushion and to generate pressure within the combustion chamber , the end cap at least in part containing an initiator that upon actuation initiates reaction of the pyrotechnic material ; and an overwrap about at least a portion of the inflator subassembly , the overwrap comprising a composite of fibers and a resin matrix system, characterized in that additionally a diffuser assembly is disposed adjacent the second end of the shell member in an outwardly extending direction, the diffuser assembly including a plurality of flow control features for controlling flow of product gas from the inflator assembly ; the overwrap extends about at least a portion of the inflator subassembly and the diffuser assembly to form the pyrotechnic inflator assembly that withstands the pressure generated within the combustion chamber upon reaction of the pyrotechnic material ; and the shell member closed second end comprises breakout pressure-controlling scoring or the shell member closed second end comprises a seal disposed onto a shell member opening at the second end , wherein the diffuser assembly comprises: a central gas diffuser element and a controlling orifice element at least in part disposed between the central gas diffuser element and the second end of the shell member , the diffuser element comprising a plurality of product gas discharge openings . a shell member having an inner surface , an outer surface , an open first end and a closed second end opposite the first end ; an end cap joinable with the shell member to at least in part enclose the open first end of the shell member to form an inflator subassembly , the inflator subassembly containing a quantity of pyrotechnic material and at least in part defining a combustion chamber wherein at least a portion of the quantity of pyrotechnic material is reactable to form product gas for inflation of an associated airbag cushion and to generate pressure within the combustion chamber , the end cap at least in part containing an initiator that upon actuation initiates reaction of the pyrotechnic material ; and an overwrap about at least a portion of the inflator subassembly , the overwrap comprising a composite of fibers and a resin matrix system, characterized in that additionally a diffuser assembly is disposed adjacent the second end of the shell member in an outwardly extending direction, the diffuser assembly including a plurality of flow control features for controlling flow of product gas from the inflator assembly ; the overwrap extends about at least a portion of the inflator subassembly and the diffuser assembly to form the pyrotechnic inflator assembly that withstands the pressure generated within the combustion chamber upon reaction of the pyrotechnic material ; and the shell member closed second end comprises breakout pressure-controlling scoring or the shell member closed second end comprises a seal disposed onto a shell member opening at the second end , wherein the diffuser assembly comprises: a central gas diffuser element and a controlling orifice element at least in part disposed between the central gas diffuser element and the second end of the shell member , the diffuser element comprising a plurality of product gas discharge openings . <EOS>