Rimfire is not exempt, but the tubular magazine feeding device used on some guns are (Marlin 60 and variants for example). This is a fairly common misunderstanding.
California Law is basically the same as our own law here
State of California Dept. of Justice website
12020 thru 12040 Unlawful Carrying and Possession - Dangerous Weapons Control Laws - Dangerous Weapons Control Laws - Bureau of Firearms - California Dept. of Justice - Office of the Attorney General
ARTICLE 2. UNLAWFUL CARRYING AND POSSESSION OF WEAPONS
12020.
(25) As used in this section, "large-capacity magazine" means any ammunition feeding device with the capacity to accept more than 10 rounds, but shall not be construed to include any of the following: (A) A feeding device that has been permanently altered so that it cannot accommodate more than 10 rounds. (B) A .22 caliber tube ammunition feeding device. (C) A tubular magazine that is contained in a lever-action firearm.
California Law is basically the same as our own law here
State of California Dept. of Justice website
12020 thru 12040 Unlawful Carrying and Possession - Dangerous Weapons Control Laws - Dangerous Weapons Control Laws - Bureau of Firearms - California Dept. of Justice - Office of the Attorney General
ARTICLE 2. UNLAWFUL CARRYING AND POSSESSION OF WEAPONS
12020.
(25) As used in this section, "large-capacity magazine" means any ammunition feeding device with the capacity to accept more than 10 rounds, but shall not be construed to include any of the following: (A) A feeding device that has been permanently altered so that it cannot accommodate more than 10 rounds. (B) A .22 caliber tube ammunition feeding device. (C) A tubular magazine that is contained in a lever-action firearm.