Abstract: An inflator (14) includes a structure (50, 70, 90) that helps define a chamber (42) from which inflation fluid flows. The structure (50, 70, 90) includes an end cap (90) having a side wall (92). A closure member (104) is rupturable to release inflation fluid from the chamber (42). An initiator (230) is actuatable to rupture the closure member (104). A filter retainer (170) includes a side wall (172) that defines a cavity (176). The side wall (172) of the filter retainer (170) includes a rim portion (196) that forms a terminal end of the side wall. A filter assembly (120) is positioned in the cavity (176) of the filter retainer (170). First segments (260) of the rim portion (196) are deformed to clamp the filter assembly (120) to the filter retainer (170). Non-deformed second segments (262) of the rim portion (196) engage an inner surface (264) of the side wall (92) of the end cap (90). The second segments (262) help position the end cap (90) and the filter retainer (170) coaxially with each other.