(I try to ignore anything to do with the People's Republic of California whenever possible. To me, they are an demonic island about 3 miles off the DPRK.)
I'm going to do some law research work tonight to see if I can find the Reporter citation where challenges to the DC action have failed. NYC requires the 'registration" of all firearms, but I want to see how (the idiots) ban all firearms. My law degree is VERY rusty (smart enough to never practice) and I believe there were no outright bans when I sat for the Bar, but since it now effectively so, I want to see the Courts holdings on this.... and I bet I am going to disagree vehemently with their ruling.
As a matter of course, I generally dislike the courts saying I cannot do something, unless my doing so would DIRECTLY affect the RIGHTS of others.
Because of that, there's nothing in the state constitution that would prevent the California legislature from banning all guns. If they did, however, there would probably be a federal constitutional challenge since the states are expected to defend the republic (via the organized and unorganized militias) and totally disarming the public would prevent that.