While I lived in CA I frequently consulted
Peace officers' guide to California's dangerous weapons laws: 101 concepts dealing with the possession, display, and use of dangerous weapons and firearms which I found very illuminating. There are a great many ordinary weapons that can land you in jail there.
I should find my copy and sell it, to someone still there. It's somewhat out of date because the anti-self defense laws have grown, but it's still informative I think. It was written by a cop in north San Francisco Bay area I think, specifically to train cops.