1) Any infringement (Merriam-Webster: "an encroachment or trespass on a right or privilege") is UNCONSTITUTIONAL per the Second Amendment to the United States Constitution.
2) FOPA reads:
"No such rule or regulation prescribed after the date of the enactment of the Firearms Owners’ Protection Act may require that records required to be maintained under this chapter or any portion of the contents of such records, be recorded at or transferred to a facility owned, managed, or controlled by the United States or any State or any political subdivision thereof, nor that any system of registration of firearms, firearms owners, or firearms transactions or dispositions be established."
(NFRTR is pre-FOPA)
FOPA hasn't stopped DC. Or HI. Or NY. Or 3310.4 forms. Etc, etc, etc.
"Show me the man who doesn’t want his gun registered and I will show you a man who shouldn’t have a gun" - AG Homer Cummings (D)