Three paradigms can be used to explain weapon lethality: rational choice and deterrence theory; social learning and cultural theory; and opportunity and prevalence theory. Each makes distinct predictions regarding the economic, psychological, and environmental factors that affect the use of weapons. Despite their merits, the sum of knowledge about violence and weapons may be increased by exploring the influence of variables derived from another paradigm: pure sociology. Black's theory of retaliation and Cooney's principle of predation provide the underpinning for a social structural-based theoretical principle of weapon lethality. Building on those ideas, we propose that the lethality of weapons involved in interpersonal violence increases as the offenders and victims become less intimate and less alike culturally. Using National Crime Victimization Survey data, the study test two hypotheses derived from this principle and primarily find support of the proposed social structural principle. (Published Abstract)