Tracking the Untraceable: The Impact of PMF Availability & Legislation on Firearm Crime

Abstract

This paper evaluates the impact of Privately Made Firearm (PMF), or “ghost gun,” availability and legislation on firearm crime in the United States. The use of PMFs in crime expanded significantly in the 2010s, primarily due to the sale of “ghost gun kits,” which include the necessary component parts to build a fully functioning firearm. These kits were intentionally marketed as an unregulated and untraceable means of assembling a working firearm. Through a descriptive study of PMF recoveries and firearm homicide rates in California and nationwide, I analyze the relationship between PMF availability and firearm homicide rates, using PMF recoveries as a percentage of all crime gun recoveries (referred to in this paper as “Percentage PMF Recoveries,” or “PPRs”) as a proxy for PMF availability. I then conduct a panel regression analysis focused on states with existing restrictive PMF laws, and analyze changes in firearm homicide rates among the same populations before and after policy implementation. The results indicate a potential positive relationship between PPRs and firearm homicide rates, and a large and statistically significant decrease in total annual firearm homicide rates and male annual firearm homicide rates after the enactment of a PMF policy. The latter finding suggests strong evidence for a causal effect of PMF policies on firearm homicide rates in the states in which these policies are implemented.