[thegundude]

To the best of my knowledge, there is no "system" for tracking gun serial numbers since it is illegal for the government to maintain such a list.

The closest thing there is to a tracking system, as such, is the dealer logs. But those logs aren't then fed into some bigger system.

This is how it works to the best of my understanding.

The manufacturer ships it to a dealer or wholesaler and logs that transaction with serial number out of their books. The dealer receives it, logs it into his books with serial number and puts it on the shelf or calls the customer who ordered it. The serial number is then written onto the proper forms when the customer takes delivery of it and logged out of the dealers book with the new owners name attached.

So, if the government wanted to know where a certain serial number gun came from, they go to the manufacturer and start following the paper trail. They don't maintain a list of serial numbers and owners, partly because they're not allowed to and partly because they don't have to. They can just call the manufacturer and do a little leg work.