@Suppressed I'd make a quip about bangles and bracelets, but many have beaten me to it ;). Good job, @Cyber Liberty, @edpc, and @Suppressed!
As for registration, as far as I'm concerned registration already exists at the level of the gun stores. And I don't care. Anyway, I'm done wrestling with that pig.
Sorry, but there is a difference between filling out a Form 4473 and being required under penalty of law every firearm you own. Many have firearms which antedate the Gun Control Act of 1968, which have had no paperwork filled out on them, ever. Some were even bought by putting a check and an order form in the mail (that's how it was back when), and some were either handed down, gifts, or purchased privately. All lawfully acquired, lawfully owned, but NOT registered nor documented. While some of the more statist jurisdictions require that, and even permits to
purchase a firearm, even today (thankfullly) there are some places in this country you can walk into a shop and walk out (Now, after filling out the Form 4473 and the NICS check) with the firearm. No paperwork nor documentation is required for private sales or gift transfers of ownership in those jurisdictions.
My point is that there are many firearms out there which have never been documented as they changed hands, and haven't been documented since they were shipped from the manufacturer to the store/dealer in the days when that was where the trail ended. It is no wonder that those command a premium over those which have, all else being equal.
