New and used handguns sold in California by a firearms dealer must be listed on the California Bureau of Firearms Roster of Handguns Approved For Sale’ website. Go to http://certguns.doj.ca.gov/, select a manufacturer [or all] from the drop-down menu, then click FIND. There are 1303 models in the database. If it doesn’t appear on this list, the handgun you seek is not approved for sale in California by a licensed firearms dealer. Active full time California law enforcement members are exempt from this requirement.
RIFLES AND SHOTGUNS
Long guns are prohibited from having magazines that have a capacity exceeding ten rounds. Detachable magazines are required to be equipped with a ‘bullet button’ magazine release. There is a lot more information regarding nomenclature for rifles and shotguns than what appears here.
A recent 2017 court decision in California no longer makes it a criminal offense to possess large capacity magazines for handguns and rifles in California.
GUN OWNER’S EDUCATION
It is the purchaser’s responsibility to educate himself with regard to California’s Assault Weapons Laws. The California Bureau of Firearms website will get you started.