The Home Office has opened an £8m National Ballistics Database service to help police solve crimes involving firearms.
The CSI-style service works by giving guns and bullets a "fingerprint", which can then be tracked.
Once a gun has been fired in a crime and identified by the service, investigators will be able to track any bullets subsequently fired from that weapon back to it.
The government said the new service will help to identify those who import, store and supply illegal firearms, and track down people involved in illegally adapting firearms.
Home secretary Jacqui Smith said, "Every gun or bullet tells a story. The National Ballistics Intelligence Service (NABIS) helps police unravel that story and track down offenders.
"NABIS's expert advice will help police take more guns off our streets and better protect our communities from gun-related crimes."