“”This is where microstamping comes in. If it were required, every gun would need to have a microscopic code stamped on the tip of its firing pin. When a bullet leaves the gun, its shell casing would be stamped with the code, which could be retrieved from the casings found at crime scenes. The code could lead the police to the person who fired the gun — or at least to its original purchaser.””
Of course, the Bad Guys would be standing in line asking to have their illegally obtained guns microstamped before anyone else.
As someone here once mentioned to me: Police your brass, then throw a whole bunch of other shell casings around.
A couple hundred rounds of wore out spent brass would keep LE busy for quite awhile.
"Microstamp" criminals, not guns