But...
From the NRA CA page:
(2) antique firearms, which are defined as: any firearm not designed or redesigned for using rimfire or centerfire ammunition and manufactured in or before 1898 (including any matchlock, flintlock, percussion cap or similar type of ignition system or replica thereof, whether actually manufactured before 1898) and also any firearm manufactured in or before 1898 using fixed ammunition which is no longer manufactured in the U.S. and is not readily available in the ordinary channels of commercial trade;
The NRA page is screwed up. That is an incorrect quote of California law. The definition given is from Section 47
9.11 of 27CFR and applies to firearms regulated under the National Firearms Act. California uses the definition in 27CFR 47
8.11 which is as follows:
TITLE 27--ALCOHOL, TOBACCO PRODUCTS, AND FIREARMS
CHAPTER II--BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES,
DEPARTMENT OF JUSTICE
PART 478_COMMERCE IN FIREARMS AND AMMUNITION--Table of Contents
Subpart B_Definitions
Sec. 478.11 Meaning of terms.
When used in this part and in forms prescribed under this part,
where not otherwise distinctly expressed or manifestly incompatible with
the intent thereof, terms shall have the meanings ascribed in this
section. Words in the plural form shall include the singular, and vice
versa, and words importing the masculine gender shall include the
feminine. The terms ``includes'' and ``including'' do not exclude other
things not enumerated which are in the same general class or are
otherwise within the scope thereof.
* * * * * * * * * * * * * * * * * * * *
Antique firearm. (a) Any firearm (including any firearm with a
matchlock, flintlock, percussion cap, or similar type of ignition
system) manufactured in or before 1898; and (b) any replica of any
firearm described in paragraph (a) of this definition if such replica
(1) is not designed or redesigned for using rimfire or conventional
centerfire fixed ammunition, or (2) uses rimfire or conventional
centerfire fixed ammunition which is no longer manufactured in the
United States and which is not readily available in the ordinary
channels of commercial trade.
Notice that the limitation on fixed ammunition only applies to
replicas of antique firearms.