Abstract: Vulnerability/lethality (V/L) tools used to assess weapons effects in targets often need some kind of rule to assess the status of each vital component being hit. The target functionality on a system level can then be decided based on which components are functional or non-functional (killed). Rules of this kind are often referred to as component kill criteria. Descriptions of component kill criteria and methods to assess them are rare in scientific journals, probably due to economic values, classified V/L tools, as well as classified input data to the tools. This paper presents the results from an experimental study of a target component, a relay, impacted by steel spheres and the component’s response to the impact. A first set of kill criteria based on impact energy and momentum are presented. Studies of the kind presented in this paper cannot be performed unless the component is cheap and readily available, conditions that many components in a military platform do not meet. For that reason and others discussed, methods and models for assessing component kill criteria should be derived from experimental studies on available components and then hopefully be sufficient also for component types that cannot be tested