What does 'registered' mean? All of my firearms have been bought legally with the appropriate paperwork, but so far as I am aware, none of them are 'registered' ... this sounds suspiciously like a central database of gun owners with their types of weapons, and available to law enforcement. Correct me is I am wrong, but that is not supposed to exist.
My recollection only, YMMV, IANAL, IANALEO, etc.
Federal form 4473's need to be filled out by the gun stores, I believe after GCA68 or so. The forms themselves stay at the store until the store owner closes the business at which time the store owner is required to give them to the feds. 4473s are supposed to be on hand for BATF inspection (strictly speaking requires warrant with good reason on particular individual).
Brady Act required background check info at FBI level to be destroyed within 90 days.
Maryland has some form of independent gun registration initiated at point of sale.
Bottom line is those who purchased guns legally are targets of a sweep which was not mandated at federal level by law though poss. at Maryland state level.
I believe there was a relatively recent case about Chicago getting 4473s from potentially the entire country, and appeals were denied.
Of course the 4473s, etc. are relatively incomplete in terms of who actually possesses guns, and in particular tend to leave out criminals (big surprise).
FBI using store 4473s for tracking down is to some degree a violation of the existing federal law as I see it.
So bottom line is that this is another potential gradual usurpation of citizens' rights. The boiling frog scenario. We are seeing yet another rise in the temperature of the soup pot, one that lawmakers at one point in time told us would not be permitted to happen.
Folks who are really knowledgeable this stuff, feel free to correct and add. I'm not so knowledgeable as disgusted.
Cheers...