California Code, Penal Code - PEN § 32610

(a) The sale to, purchase by, or possession of machineguns by a police department, a sheriff's office, a marshal's office, a district attorney's office, the California Highway Patrol, the Department of Justice, the Department of Corrections for use by the department's Special Emergency Response Teams and Law Enforcement Liaison/Investigations Unit, or the military or naval forces of this state or of the United States for use in the discharge of their official duties, provided, however, that any sale to these entities be transacted by a person who is permitted pursuant to Section 32650 and licensed pursuant to Article 4 (commencing with Section 32700).

(b) The possession of machineguns by regular, salaried, full-time peace officer members of a police department, sheriff's office, marshal's office, district attorney's office, the California Highway Patrol, the Department of Justice, or the Department of Corrections for use by the department's Special Emergency Response Teams and Law Enforcement Liaison/Investigations Unit, when on duty and if the use is within the scope of their duties.