In CA both long guns and handguns must be transfered through an FFL, here's how it's done.
Say you find someone at the show who's selling something you want. You both find a dealer there at the show that is local to you(many dealers now have signs reading "transfer dealer" or something similar). You both fill out all necessary paperwork, and show ID, and you give the owner of the firearm the agreed-upon price. You guys then go your separate ways. The dealer then KEEPS the firearm for 10 days, which is actually 11 days since it starts the next day. You of course have to pay the dealer to keep the gun for you, minimum $20 for the transfer. After the 10(11) days, you're free to go to the dealer's place of business, and sign again before taking posession of your new firearm.
It only sounds like a pain in the rear because IT IS!!! It's especially a pain if you're at a show out of town.
Oh yeah- You can only buy one handgun per month in the PRK. I was originally told that the law doesn't apply to private party transfers, but recent evidence has shown that it does.
This state is beautiful, huh?