Pre- and postenactment comparisons indicate that the number of weapons possession charges against those already charged with a felony decreased, while the number of arrests for the sole crime of criminal use of a gun increased. Indictments for weapons possession and processing through final court disposition also showed increases following enactment. Most charges resulted in misdemeanor or nonviolent felony convictions. Serious firearm felons were likely to have additional gun charges dropped in favor of the felony charge. Those convicted of gun-related crimes were more likely to receive jail or prison sentences after enactment of the law. There was no significant change in the number of citizen or police reports of crimes involving guns, nor was there any evidence that the law and its mandatory incarceration provisions resulted in increased use of other dangerous weapons. Finally, firearm use in assault, rape, and robbery was not reduced by the new law. 28 notes and approximately 200 references.