Identifying the firearm used in a crime is one of the biggest challenges for criminal investigators. But what if a shell casing picked up at a murder scene could immediately be tracked to the gun that fired it? A technique that uses laser technology and stamps a numeric code on shell casings can do just that. But the technology, called microstamping, has been swept up in the larger national debate over gun laws and Second Amendment rights, and efforts to require gun... (GunPolicy.org)