I beg to differ, you can't purchase a firearm in Hawaii if you don't have a permit and you can't own it (legally) if you don't register it.
The test of a gun law is whether it has any effectiveness at preventing or solving gun-related crimes.
In Maryland, they went a step further and registered not just serial numbers, but they also kept a fired casing from each gun and created a searchable database. Their "dream" was to have a way to match the spent casings found at a crime scene (i.e. inside a dead body) and identify whose gun fired it.
After FIFTEEN YEARS and $5M to setup and run the program, the system didn't solve a single crime. So, they scrapped it.
Firearm registration, likewise, might be a convenient research tool for Cops when tracking down owners of given firearms that may have been used in crimes, but there's little the registration system does to PREVENT any crime.
There is legal precedence where courts decided that a person ineligible to legally own a firearm can't be charged for failing to register the firearm as required by law. To do so violates the Constitution's 5th Amendment against self-incrimination. So, criminals can LEGALLY abstain from gun registrations, whereas legal gun owners cannot.
The ONLY FUNCTION of a registration system is for (1) confiscations, and (2) enforcing background check laws for private sales.
Confiscations can be unconstitutional sweeping confiscations or just individual owner confiscations -- e.g. someone is adjudicated no longer permitted to own guns, authorities will know what guns to search for.
When someone sells a gun on the private market, and if there's a law requiring background checks for the private buyers, the seller could just ignore the law if the buyer wasn't required to report the sale to the state via registration. Therefore, only law-abiding owners will register guns. No crimes were prevented, other than compliance with gun registration laws.