California Code, Penal Code - PEN § 32670

(a) Except as provided in subdivision (b), the Department of Justice shall, for every person, firm, or corporation to whom a permit is issued pursuant to this article, annually conduct an inspection for security and safe storage purposes, and to reconcile the inventory of machineguns.

(b) A person, firm, or corporation with an inventory of fewer than five devices that require any Department of Justice permit shall be subject to an inspection for security and safe storage purposes, and to reconcile inventory, once every five years, or more frequently if determined by the department.