Abstract: A dual component caulking gun which utilizes a gun body to which there is affixed a dual component cartridge assembly designed to carry dual component cartridges. A ball screw is journaled within the gun body for rotary motion but locked against axial motion and extends in a direction opposite the component cartridge assembly. A pair of ram rods are journaled through the gun body and terminate at the first end in ejector rams and at their opposite end in a transfer bar that is interconnected to the ball screw by means of a ball screw nut.

Abstract: An adjustable piston packing expander for use with conventional caulking gun piston assemblies is disclosed. The packing expander threads onto the piston rod and includes a frusto-conical expansion surface which contacts the inner surface of the packing wherein advanced threading of the packing expander onto the piston rod will adjustably expand the packing into sealing engagement with the gun barrel walls. A set screw locks the packing expander in adjustment relative to the packing. A lock washer keyed to the square piston rod and interlocked to a rear piston rod washer having locking pins extending into the packing and forming a part of the piston assembly interlocks the packing against motion relative to the piston rod.