Gun control policies must strike a balance between conserving legitimate use of handguns and reducing criminal use. Current federal law seeks to accomplish this objective by discriminating between safe and unsafe gun owners-allowing the former and prohibiting the latter from owning guns. An important practical problem soon arises: containing guns within the entitled sector. Analysis of the current supply system suggests that gun offenders acquire guns from many different sources: purchases from licensed dealers, private transfers, thefts, and black markets. Among these, legitimate purchases seem most important in supplying assaulters, and thefts seem to be the most important in supplying armed robbers. The “black market” turns out to be difficult to distinguish from the other sectors. To the extent it is distinct, it seems to be populated primarily by small-scale, impermanent enterprises, rather than durable firms. Analysis of how existing institutions might be deployed against this system leads to the conclusion that local enforcement capacities and federal regulatory efforts are the most important operational capacities to develop. Federal criminal investigation capabilities are important only for limited purposes.