Jeff,
The applicable section of the law is California Penal Code section 12025.
It is only a felony if the person is a felon, if the firearm is stolen, if the person is a member of a criminal street gang as defined in section 186.20, or if the person is not "in lawful possession" of the firearm or are a prohibited person under federal or state law.
It's a misdemeanor if the person is not the registered owner of the firearm, or otherwise. The three-month minimum sentence only applies if there's a previous conviction of "violent use of a firearm."
Check out
http://www.equalccw.com/ for some gory details.
Jim March might well suggest formally applying for a license, and if you're rejected and later had to use your firearm in defense of yourself or your family, your lawyer would have a better shot at mounting an affirmative defense against a 12025 prosecution, perhaps using 12025.5(b).
The general suspicion is that they made a first offense a misdemeanor because otherwise all the friends of the politicians would be getting snared.
Hypothetically speaking, I carried on a few occasions before I moved from San Jose to New Hampshire, and one incident that really got my guts in a knot was when someone cut in front of me on my motorcycle in San Francisco, and we wound up pulling off the freeway right next to the jail and around the corner from the police station.
After I finished the accident report with the police officers who showed up, all the while intensely conscious of the danger I faced from them for exercising my right to self-defense, I realized that what I'd thought was a bruise on my leg was actually the fuel petcock having been driven into the side of my calf.
Since there was no possible way I was going to go anywhere near a San Francisco hospital with a firearm on my person, I wound up shoving some gauze into the wound and wrapping it up a bit, and making the 50-mile ride home where I dropped off my pistol and went to the hospital for stitches. I also discovered that evening that the Metreon Theater didn't keep a first aid kit.
The ironic thing is I was accosted, threatened, and had a bottle thrown at me by a couple of San Francisco's notoriously surly and demanding homeless that evening, and was very relieved to have been armed.
That's the problem, though - you never know what could happen. If I'd been knocked unconscious instead of just getting crunched a little bit, I could have been in some deep manure.