Abstract: Restricting outlet fluid flow from a pressure vessel includes an inlet/outlet member having a passage of predetermined dimension communicating with the pressure vessel. The pressure vessel is initially filled with fluid through the passage at a first flow rate. A restrictor is adapted for close receipt in the inlet/outlet member passage and includes an opening having a dimension substantially less than the inlet/outlet member passage. An outer end of the inlet/outlet member is thereafter deformed to retain the restrictor insert within the passage. Fluid flow released from the pressure vessel must exit through the restrictor opening at a second flow rate substantially less than the inlet first flow rate.