Cal. Penal Code § 30310

(a) Unless it is with the written permission of the school district superintendent, the superintendent’s designee, or equivalent school authority, no person shall carry ammunition or reloaded ammunition onto school grounds, except sworn law enforcement officers acting within the scope of their duties. (b) This section shall not apply to any of the following: (1) A duly appointed peace officer as defined in Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2. (2) A full-time paid peace officer of another state or the federal government who is carrying out official duties while in California. (3) Any person summoned by any of these officers to assist in making an arrest or preserving the peace while that person is actually engaged in assisting the officer. (4) A member of the military forces of this state or of the United States who is engaged in the performance of that person’s duties. (5) An armored vehicle guard, who is engaged in the performance of that person’s duties, as defined in subdivision (d) of Section 7582.1 of the Business and Professions Code. (6) Any peace officer, listed in Section 830.1 or 830.2, or subdivision (a) of Section 830.33, whether active or honorably retired. (7) Any other duly appointed peace officer. (8) Any honorably retired peace officer listed in subdivision (c) of Section 830.5. (9) Any other honorably retired peace officer who during the course and scope of his or her appointment as a peace officer was authorized to, and did, carry a firearm. (10) (A) A person carrying ammunition or reloaded ammunition onto school grounds that is in a motor vehicle at all times and is within a locked container or within the locked trunk of the vehicle. (B) For purposes of this paragraph, the term “locked container” has the same meaning as set forth in Section 16850. (c) A violation of this section is punishable by imprisonment in a county jail for a term not to exceed six months, a fine not to exceed one thousand dollars ($1,000), or both the imprisonment and fine.