On first glance the proposal sounds reasonable. After all, it would certainly be a help to law enforcement to be able to tell from a spent casing not only what caliber gun was used in a crime, but also to know the make and serial number of the gun that fired it. But the proposal reportedly also contains a kicker: "The measure requires that when a weapon is sold, the dealer notify the state police of the ownership change." This implies that all sales would have to occur through a dealer, no private transfers, and the result would be, in effect, a comprehensive registration system. The authorities would maintain a master list showing at all times who owns what guns. This goes way beyond simply allowing the identification of a gun from a spent casing. The vast majority of guns are never used for any unlawful purpose, so the primary effect of this proposal would be to register law-abiding gun owners and their guns.