A dispensing gun assembly includes a frame, a rod, a piston, a driver, a trigger, and a linkage. The rod slideably connects with the frame for linear movement with respect to the frame. The piston connects with the rod for movement with the rod. The driver selectively engages with the rod to move the rod in a linear direction when engaged with the rod. The trigger slideably connects with the frame. The linkage connects the trigger with the driver such that linear movement of the trigger with respect to the frame in a rearward direction results in the driver engaging the rod and linear movement of the rod and the piston in a forward direction.