The studies do not provide strong evidence that smaller caliber handguns are more often used in crime than are larger caliber weapons. For example, the BATF study of the types of guns used in crimes found that 45 percent of the 10,617 crime guns submitted by police could be classified as SNS's. However, the BATF data may be an unreliable index because 25 percent of the weapons were either found or turned in, were usually related to crimes of illegal possession of a firearm, or were owned by police officers. Brill's Police Foundation study, which controlled for these variables, indicated that approximately 30 percent of the crime handguns were SNS's. Finally, at least 75 percent of black homicides in St. Louis in 1970, 1973, and 1975 were firearm homicides; at least 60 percent or more were handgun homicides. However, smaller caliber handguns which qualify as SNS's were not used in homicides as often as larger caliber weapons. While there is little agreement on the potential impact of national legislation banning the manufacture and distribution of SNS's, the key issue remains the substitution effect. SNS prohibition proponents see little substitution or envision substitution with less lethal weapons. Opponents contend there will be more substitution, with more lethal weapons, resulting in more death. More empirical research on substitution is needed to establish reasonable and effective public policy on SNS's. Tabular data and 34 footnotes are provided.