Cal. Penal Code § 27534

(a) A person who modifies a microstamping-enabled pistol or microstamping component with the intent to prevent the production of a microstamp is, for a first offense, guilty of a misdemeanor punishable by imprisonment in the county jail not exceeding six months, by a fine of not more than one thousand dollars ($1,000), or by both that fine and imprisonment, and for a second or subsequent offense, is guilty of a misdemeanor punishable by imprisonment in the county jail of not more than one year, by a fine of not more than two thousand dollars ($2,000), or by both that fine and imprisonment.
(b) Subdivision (a) shall not apply to a pistol manufactured prior to the effective date of this section.
(c) For the purposes of this section, it shall not be unlawful to replace the microstamping component of a microstamping-enabled pistol when the component is damaged or in need of replacement with another valid microstamping component for the safe use of the firearm or replacing a microstamping component for a legitimate sporting purpose.