Abstract: A paint spray gun of the airless type is disclosed. The spray gun includes a central passageway for delivering liquid paint under pressure to a spray tip having an elongated, sharp edged spray opening and a pre-orifice adjustable in cross-sectional area positioned upstream in the passageway from the spray opening. The pre-orifice is formed by an elastomeric member having an opening therethrough co-axially aligned with the passageway and the spray opening. The elastomeric member is arranged for axial loading and elastic deformation to vary the cross-sectional area of the pre-orifice opening by operation of a control knob externally mounted on the body portion of the spray gun.