The problem with questions like this are many fold.
First of all people tend to look at it like “If it solves ONE crime it’s worth it.” And that’s nice from a humanitarian view but it doesn’t work in real life. For instance, I read studies wanting to raise the drinking age to 25. That would save lifes. But would we? Would the cost outweight the people skirting the law.
Second of all how would you do it so people can’t defeat it. You don’t make a law that is unenforceable. Remember there will be people purposely setting out to make the law undoable.
In additon how would you lable the bullets, each bullet has it’s own number? Or does a box of say 100 have the same number. Let’s say I don’t like this law, I buy a box of bullets and report them to the cops stolen. Then I purposely leave them in a high crime area. The bullets are stolen and used.
If the bullets are individually numbered supposing I reported that bullet number stolen and I keep it. Does the fact that a gang guy who has bullet F123 and F125 in his possesion prove he had F124? Or could I have used it and set this gang guy up?
If it’s a box of 100 bullets having the same number, I simply report the whole box stolen and keep a bullet. If I report a 100 bullets stolen, am I resonsible for them if one fell out of the box in my closet and 10 years later it shows up?
What about unmarked bullets now? All it does is create a black market for them. I know this bill will pass, I stock up, then sell the unmarked stuff at premium rates and they get laundered to crooks.
As I read the posts the the people that favour this idea see it as “If it solves even ONE crime, it’s worth it.” Maybe it is. The people against this idea seem to say “Why pass a bill that will create a situation that isn’t enforceable and will cost millions.”
Sometimes you have to put a cost on human life. It’s hard to admit but you do it. Supposing your son has a rare illness that effects only 50 other people in the USA. Does the government put any money into studying that illness? Or do we put the money in other illnesses where it helps.
You have to ask, does the benefit of even solving ONE crime, outweigh the costs. (And obviously more than one crime is likely to be solved.)