Abstract: A novel water gun is disclosed herein having a body formed with a central bore opening at its opposite ends to provide a discharge nozzle at one end of the body and a storage compartment or reservoir end at the opposite end of the body. The storage compartment end is adapted to releasably hold the end of an inflatable member which when loaded with water under pressure, expands so as to stretch the membrane of the inflatable storage compartment. Upon termination of the loading pressure, the inflatable member collapses under its own elasticity to discharge the stored water via the nozzle end of the body. A clamping device is employed for detachably connecting the inflatable storage compartment to its respective end of the body and a trigger mechanism may be employed for selectively releasing the pressurized water within the storage compartment.