I've always had a wry chuckle for this idea that "we don't have a national gun registry."
Sure we don't.
The retailers maintain a distributed registry for the government. Technically the government doesn't maintain this registry.
Oddly, however, through a sort of business attrition, the government winds up holding this "distributed registry" until, gradually, save only for the data entry marathon, they have a record of every retail (and many private) gun purchases for the last twenty or more years.
And then the entertainment industry, through shows like CSI and NCIS, keep hammering the meme that "such-and-such a gun was registered to so-and-so," or perhaps, "yeah, but his gun was unregistered," implying that "guns are registered," and one day the population wakes up to de facto registration, but no one is surprised since -- culturally -- aren't all guns supposed to be registered?
Nope. No registration here. Move along now.