First of all, neither gun owners nor true privacy advocates are willing to stand for the notion of "de facto" gun registration by registering every purchase of ammunition made and storing it in a database.
Secondly, we're in enough of an economic crisis without the government having to compensate citizens for the hundreds of millions of rounds of non-coded ammunition that your legislative lapdogs are calling for us to hand over and/or destroy. I assume we WOULD be compensated for them, right? Otherwise...well, last I checked, taking someone's property without permission, consent, or compensation was called robbery. We don't take kindly to thieves in my parts, and no where else in the United States for that matter.
Third, only a fool would think that this will be a great boon in fighting crime. You may not be aware of it, but there are handguns called "revolvers" that do not spit out spent brass with each shot...it must be manually removed. Also, it might interest you to know that there are long guns that require a manual action (working a bolt or a pump for instance) to eject spent brass. What kind of moronic criminal would then choose to eject and leave the brass at a crime scene?
I guess you get what I think of you and your little idea by now, hmm? If you'll pardon the pun, anyone capable of rational thought can "blow holes" in your theories that this will actually be a great help in fighting crime. In my opinion, you're nothing but a bunch of CON MEN, trying to peddle a very modern version of snake oil to gullible state governments, in return for a false promise of being able to catch every criminal that uses a gun. I'm sure that the fact that $100-a-box ammunition will all but destroy the Second Amendment means little to you as well. To say nothing of all the poor, deluded folk that may be lulled into a false sense of security in any area with a legislature incompetent enough to pass the ammo ban you seek. It's honestly a textbook example of a "feel-good" law.
I see you've suffered several legislative defeats so far, but I somehow doubt that will stop your pursuit of this "con" to the fullest. Know that I and millions of others like me will not stand idly by and allow you to defraud our government and our people!