• Ballistics evidence includes shell casings - the most valuable form of evidence - and bullets.
• If police recover a shell casings or bullets, ballistics technologies can help connect that crime to particular guns and often to perpetrators.

• Example 1: NIBIN - The nationwide database of crime scene evidence run by ATF.
  • NIBIN includes evidence recovered from crime scenes, so it may offer a lead by connecting a gun to a prior crime. However, it will not disclose:
    • What dealer first sold the gun at retail;
    • Whom they sold it to;
    • Whether it is registered and, if so, to whom.
  • NIBIN relies on the tiny marks that a gun leaves on a cartridge when it is fired.
    • Comparing these marks is very difficult; it is an art as much as a science, and even if a computer identifies a possible match, a forensic expert must confirm it.
• Example 2: Microstamping - This state-of-the-art technology lets police who recover ballistics evidence at a crime scene identify the gun that was used.
  • When fired, each gun will automatically stamp its serial number onto the cartridge casing in at least two places.
    • If police find a casing from a gun that was sold in a state where handguns must be registered, they can look up its owner.
    • Even if the gun is not registered to anyone, ATF can trace it to the first retail buyer.
  • Microstamping will be used only for semiautomatic pistols, not for revolvers (which do not discard shell casings) or long guns (which account for only a small share of gun crime).
  • The only peer-reviewed study found that microstamping has at least 54% success rate.
    • That means over a 90% chance of identifying the gun if police find three casings

• California microstamping law:
  • This recently passed bill was signed into law by Governor Schwarzenegger. It will go into effect starting in 2010, and it grandfathers models of pistols that have already been approved for sale in the state by then, but requires new models of guns manufactured or sold in California to include microstamping technology.
  • Legislation to require microstamping has also been introduced in at least six other states (CT, MD, MA, NY, RI, and VA), in this session or previous ones.

California State Legislature: Microstamping (AB 1471) California law now requires that, starting in 2010, the interior surface or internal working parts of all newly-designed semiautomatic handguns in California be etched with a microscopic array of characters that identify the make, model, and serial number of the firearm. Learn more

This is a selected list of initiatives that members of Mayors Against Illegal Guns are pursuing in their cities. Please note that the programs and ideas listed on this page have not been formally endorsed by the coalition. Mayors Against Illegal Guns understands that what works in one city or town might not work in another - but mayors in this coalition have an interest in learning from each other, and these items are presented as starting points for those conversations.