California Code, Penal Code - PEN § 33220

(a) The sale to, purchase by, or possession of short-barreled rifles or short-barreled shotguns by a police department, sheriff's office, marshal's office, the California Highway Patrol, the Department of Justice, the Department of Corrections and Rehabilitation, or the military or naval forces of this state or of the United States, for use in the discharge of their official duties.

(b) The possession of short-barreled rifles and short-barreled shotguns by peace officer members of a police department, sheriff's office, marshal's office, the California Highway Patrol, the Department of Justice, or the Department of Corrections and Rehabilitation, when on duty and the use is authorized by the agency and is within the course and scope of their duties, and the officers have completed a training course in the use of these weapons certified by the Commission on Peace Officer Standards and Training.