The present invention provides a hybrid fluid flow meter pressure vessel assembly (1) that includes an interior housing (11) fabricated from plastic, and an exterior ring structure (26) fabricated from metal. Interior housing (11) has sidewalls (14) and an internal chamber (17). The sidewalls (14) of the interior housing (11) have first and second apertures (20, 23) that are each in fluid communication with the internal chamber (17). The exterior ring structure (26) encompasses at least a portion of an exterior (29) of the sidewalls (14) of the interior housing (11), and includes outwardly extending first and second conduits (38, 41) that are in respective fluid communication with the first and second apertures (20, 23) of the interior housing (11).