of the claimed invention an elongated rod 28 extends from the body 12 and is axially advanced through the body into the cartridge support assembly 14 and cartridge 24 upon activation of the trigger 20 a piston 30 is connected to a forward end of the rod 28 such that axial movement of the rod will cause comparable axial movement of the piston resulting in the dispensing of material from dispensing nozzle 26 of the cartridge 24 upon advancement motion enabling mechanisms of the rod 28 and piston 30 such as an electric motor controls and gearing are located within the body for advancement and retraction the rod and piston in the illustrated embodiment the rod 28 includes a rack or tooth portion for engagement by a pinion of a gear assembly not shown upon engagement of the trigger 20 an internal motor not shown would provide movement in the gear assembly engaging the rod 28 for either advancement or retraction of the rod through the body 12 the motion enabling mechanisms for advancing and retracting the rod 28 and piston 30 through the body 12 could alternatively be achieved by other constructions known by those skilled in the art such as a screw gear assembly without departing from the spirit and scope of the claimed invention turning now to fig2 is a partial sectional elevation view of the cartridge support assembly 14 attached to the body 12 of.