Not all. It varies from state to state, of course, but California's are among the strictest in the nation, surpassed only by Washington DC. Chicago, NYC, California, and DC all stand out as particularly restrictive.

I have a Romanian copy of a Kalashnikov (semi auto), but I wouldn't be able to possess it within the state. Nor my Saiga (the Russian one), for that matter, but that's me going of memory. I did a research paper on gun control last semester, and my memory of the specifics of California's laws is fading.