Gun registration is a moot point today, in the era of data-mining.
If you ever bought a rifle mag or ammo with a credit card, they know what you have got. And me, and all of us.
That is one reason I carry cash when I buy ammo. Never use a credit card for ammo these days. It’s probably been 20 years since I paid for ammo with a card, and that was most likely .22 or 12 gage bird shot.
That's true for recent purchases -- but firearms are designed to be robust and withstand hard use. Pretty much everyone (except my dad!) who returned from WW2 came back with a Luger or K-98. My own state has required permits for pistol purchases since the 1960s, but the permits are still paper with multiple carbon copies. The amount of time and effort to track down everything would be astronomical. And guaranteed to be inaccurate -- the state can't even handle annual vehicle registration renewals without an incredibly high error rate.
I know I have one not registered - a long rifle circa Revolutionary/Civil war. The condition is perfect - now, if I had black powder and ball, and was strong enough to lift it (weighs a ton), I could use it. It had been in my husband's family for many years.
If a rifle was that old, and someone could load it, would it blow apart?
Could this be the end of mandatory gun registration, now that it is shown to be redundant and a violation of privacy?