Abstract: The inventive cable tie gun uses simple slides and lever arms and does not require common linkages, toggles, or other complex mechanical actions that are subject to malfunction. Near the end of the tensioning slide travel, there is a mechanical interference between two moving parts (i.e. between a cable tensioning slide and a cable severing lever arm having a blade attached thereto.) However, if the cable tie tension exceeds the pulling capability of the tensioning slide, one of the moving parts is immobilized and the interference does not occur. Thereafter, the cable severing lever arm may take a full stroke and cut off the strap end while the tensioning slide is being held at midstroke position by the tension in the cable tie strap. The performance of the cable tie gun is greatly improved by a correct choice of cam surfaces, whereby the parts help and do not oppose each other.