California Code, Penal Code - PEN § 26576

(1) The sale, delivery, or transfer is to an authorized representative of a city, city and county, county, or state government, or of the federal government, and is for the governmental entity.

(2) The entity is acquiring the firearm as part of an authorized, voluntary program in which the entity is buying or receiving firearms from private individuals.

(c)(1) Notwithstanding subdivision (b), a firearm acquired pursuant to subdivision (a) may, in lieu of destruction, be donated to a public or private nonprofit historical society, museum, or institutional collection, subject to the provisions of Section 27855, including that the firearm be deactivated or rendered inoperable before delivery.

(2) For purposes of this and other sections in this title, “deactivated or rendered inoperable” means to render the firearm permanently inoperable by means including, without limitation, welding of the chamber, cutting of the barrel, chamber, or breech, plugging the barrel, or welding the bolt to the chamber.