From what I have read the proposal was to laser etch a code on each bullet. The same code going on all the rounds going into 1 box. The box would carry the ID of the rounds within. When you buy the box of ammo, the box bar code is scanned along with the buyer's ID (drivers license) and the match-up recorded in some data base. If the bullet is recovered in a crime, they read the ID number, search the data base and a team of guys in black smash through your door at 2am. They claim to have tested lots of rounds fired at lots of different target materials and that the ID is readable in better than 80% of the recovered rounds.
For you reloaders and home bullet casters, you won't be charged for unmarked bullets if you are going to or from a range or sanctioned shooting even.
They say they haven't workrd out all the details yet.
No $hit. What a nightmare.