Abstract: An easily cleaned trigger-actuated gun of simplified construction for applying a multi-component resinous patching or adhesive compound system to a workpiece is described. An internal valve positioner, connected to the trigger mechanism by means of an operating rod, regulates flow of compound from the gun, between zero, intermediate or full flow rates in response to trigger position, by adjusting clearances between simple flow checking ball elements and their valve seats at each component inlet into the gun. The metered components flow through a static mixer tube, onto the workpiece.