Are those allowed in California? It sounds like banned assault rifle.
No, they I don't think they are allowed in the Peoples' Republic of Kalifornication. They are not banned by the federal government or by most states - the red states, the fly-over-country.
AR 15.COM( This site is a lot more than AR15's)
and The High Road
..and The Firing Line
Great question! The premise is certainly stretching things a little, though, in that I seriously doubt a lost election is going to result in much but bruised feelings. But you're right to want to be prepared at all times, especially with a wife and family.
The first thing I'd do is harden your home. Metal frames on the exterior doors, metal doors or solid, heavy wood with small or no windows, and a deadbolt lock on each. Shutters on the windows if it's appropriate. Designate an interior, windowless room as a safe room, put a sturdy door and a deadbolt on it and keep a firearm and a charged cellphone inside. Train the wife and kids to retreat and button up at the sign of trouble and holler for help.
As to the firearm(s) themselves, I also like a Mossberg 500 but any decent shotgun that you've practiced with is adequate. At interior ranges the difference between birdshot and 00 buck isn't really very great. Learn to hit with what you have.
Identify lines of egress if possible should you need to take the very grave step of leaving the house. Speak to your neighbors about mutual self-defense - community defense is far more effective a deterrent to rioters than a single guy with a shotgun on his doorstep. Speak to the local police about what procedure they use and what their own plans are - you might be surprised. Store food, water, ammo, medicine if applicable, and the usual emergency supplies sufficient to last you until it becomes clear what your next step will have to be.
This is all pretty common-sense stuff and I apologize for stating the obvious to folks who probably already know it. If I remember your neighborhood rightly I don't think you're going to have a problem, but the best general advice is to help your neighbors and depend on yourself.
Well, yes and no. Many firearms are banned by make and model. But it's easy to avoid that by buying a firearm by a manufacturer that is not on THE LIST.
About the only thing that the Kalifornia "assault weapons" ban accomplishes is to inconvenience lawful gun-owners by disallowing pistol grips on semi-automatic magazine-fed center-fire rifles. Any criminal who wanted to have a banned rifle can create one in under a minute by simply adding back the pistol-grip to an otherwise legal rifle.
Anti-gunners are among the most ignorant people on the earth.