Fine. Make it like liquor sales. Illegal to buy and sell to an unqualified buyer.
Offer a free number to be able to call and check if someone is qualified (or put a mark on drivers licenses of those who are disqualified).
Do NOT collect data about who is buying what. After all the goal is not to create a confiscation database, but to make sure guns aren’t sold to criminals.
Anyone who insists on databasing the serial number and model of a gun an individual buys is clearly bent on confiscation.
Here’s how it works:
I call 612-MNCHECK.
The operator answers “Minnesota Instant Check, may I have the buyer’s name, please?”
I say “John Q. Smith.”
They ask: “Address?”
I provide that from the buyer’s drivers license. (Maybe also provide the DL number.)
“Please hold...”
“...thank you for holding...your buyer is not disqualified from purchasing firearms, thank you. Your record number for this verification is Q7KP456, please make a note of it.”
(Note that this could be entirely automated, including on the Internet.)