Fingerprints can be lifted even if you wipe down the firearm
Researchers at the University of Leicester and the Northamptonshire police have teamed up to develop a technique to see fingerprints even if a metal surface has been wiped down. When people hold metal objects, the natural residues on their hands, like sweat, corrode metal surfaces. Their technique is particularly useful with cartridge casings, because the heat from shooting the weapon helps to imprint the fingerprints on the metal.
So, we can stop all this inane chatter about ammo serialization, right? I mean, if the actual goal of things like serialization is to track the user of the weapon / ammo, then this should be fine. Unless, of course, the goal is actually to make it harder for the law abiding to have guns, then by all means, continue on.