Federal law does not include 'antique firearms' as firearms for purposes of 18 USC 922.
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California law is less forgiving; while transfer may be made without using an FFL, 'antique firearms' ARE firearms for purposes of transfer to and possession by felons, and for purposes of carry and possession by persons who are not disabled by law.
Definition
Generically a weapon made in or before 1898
CA Penal Code routinely defines Antique Firearm as those that are defined in USC 18, Sec 921(a)(16). In at least one place, CA Penal Code defines Antique Firearm as 'made prior to January 1, 1899'. In one area, dealing with 'destructive devices', it defines it according to [Section 479.11 of Title 27 of the Code of Federal Regulations.] [1]
[USC 18, Sec. 921(a)(16)][2] reads:
The term 'antique firearm' means -
Antique Remington Shotgun Serial Numbers
California law
Penal Code 16250 says
Firearm Serial Number Lookup
Antique Colt Pistol Serial Numbers
Penal Code 27500 is the prohibition on transfer to ineligibles:
Violation is punished according to Penal Code 27590
Penal Code 29800 is the punishment for an ineligible in possession
Unloaded open carry
For a very special circumstance, the ban on unloaded open carry at PC 26350 exempts unloaded 'antique firearms' through PC 16520(d)(5).