So-called ballistic fingerprinting is the Trojan Horse for universal firearm registration. What would be the purpose of keeping these records for each and every gun, unless the purchaser and holder for the gun is also registered?
Assuming that the system works (it doesn't), what is the law enforcement utility of knowing the the serial number of a gun used in a certain crime, unless they also know the whereabouts of the gun?
And of course, the system does not work. Perfect bullets are almost never recovered from crime scenes. The "fingerprint" of a gun begins to change with the first round that is fired, and can be altered by anybody, even accidentally. Have you noticed that the State of Maryland had not yet stated that the gun used in these sniper attacks is not one of the guns in their database?
OK, truth time: What is the law enforcement utility of a system that maintains information on the whereabouts of every gun, but is useless for tracking down guns used in specific crimes?
Confiscation.