|dev|null wrote on May 27
th, 2015 at 4:25pm:
No, not illegal, just done on a very small scale. Since 1986 (FOPA) the Feds have been
'virtually' locked out of the business of registration, & few States require it -- their numbers are slowly decreasing.
Want to know how many new firearms are on the street across America, you need to poll all the licensed dealers, & gun stores, & then use yer trusty calculator.

Registration to me includes Name, Address, & other personal information along with all the firearm sale information. That's nearly as rare as hens teeth.
Many of the registrations that do take place don't include name & address, or personal info, just serial number make & model, pass or fail of the background check, & are usually kept by the sellers for legally mandated book keeping purposes only, & are not transmitted to any government database. The only way the government can get their hands on that registration info is via a signed court order, which is always subject to injunction & appeal.
The NRA & other Second Amendment Organizations are very vigilant when it comes to even the suggestion or proposal of a National Registration Database. So far they're battin' a 1000 (Baseball term for being successful in every instance)