"Legislators in several states are working on laws that would require certain gun manufacturers to implement 'microstamping' to help law enforcement solve gun crimes. 'Lasers engrave a unique microscopic numeric code on the tip of a gunâs firing pin and breech face. When the gun is fired, the pressure transfers markings to the shell casing and the primer. By reading the code imprinted on casings found at a crime scene, police officers can identify the gun and track it to the purchaser, even when the weapon is not recovered.' As with any gun-related legislation, many people oppose these new laws. In California, a law passed in 2007 requires that when microstamping (which is easily defeat-able) is no longer patent encumbered, all new guns in CA must use it. To fight it, an organization called the Calguns Foundation paid a fee to extend the patent in order to prevent the law from going into effect."
http://yro.slashdot.org/story/12/06/13/215204/blocking-gun-laws-with-patents
http://yro.slashdot.org/story/12/06/13/215204/blocking-gun-laws-with-patents