Can I BUY/SELL/OWN AN UNREGISTERED FIREARM?
Frequently Asked Questions: Can I BUY/SELL/OWN AN UNREGISTERED FIREARM?
California does not require firearms to be registered.
Handguns that have gone through CA FFLs are registered through the DROS process.
Long guns, other than 'assault weapons', are not registered through DROS, since no firearm information - make, model, caliber, etc. - is recorded.
Sales since 1991 have been required to use an FFL, so nearly all transfers since then have gone through DROS.