Trace data
Via Gun Law News, blogomonicon points to some info on gun trace data:
If one accepts this argument, then one policy conclusion becomes inescapable: one-handgun-per-month laws are a failure and should be repealed. The laws specifying that citizens may purchase only one handgun per month are based on the premise that purchases of multiple handguns from gun stores are a major source of supply for interstate gun-runners. According to the Schumer study, two of the three states that supplied the most guns to New York were Virginia and South Carolina, the only states in the nation with one-gun-a-month laws at the time of the study.
