The 15 round magazines are not legal to bring into the state. Bringing the 15 round magazines with you is a major offense.
The handgun itself is legal to bring, but you will need to get magazines that can only hold 10 rounds to continue to use it.
You will also need to pay for the privelidge of registering your handguns within 60 days of moving in.
They will then enter a database that will constantly be cross referenced against new prohibited persons.
Complete and submit a NEW RESIDENT HANDGUN OWNERSHIP REPORT form along with $19.00 to the Department of Justice, one for each seperate handgun.
http://ag.ca.gov/firearms/forms/pdf/ab991frm.pdf
If you have police contacts they will be aware of any pistols registered to you, as that is added to thier computers.
If you run afoul of any of a number of misdemanors or any felonies, or are added to the mental unfit list any time in the future the database will red flag you as someone in possession that shouldn't be.
You may wish to research the prohibiting misdemeanors, they include simple assault or battery for example. If you even get in someone's face, shake your fist, or otherwise intimidate someone (an assault) it is a 10 year RKBA suspension in the state by law for example.
Welcome to CA.
A CCW permit will be much more of a pain to aquire, it can be done, but it is entirely discretionary.
I would not expect to aquire one new and just moving into that area unless you have some special needs.
San Diego CCW includes at two seperate interviews to be considered, they must be during the hours most people work during weekdays, include 3 local residents not related to you that think you should be allowed to carry a loaded firearm, and are willing to put themselves on record stating that with contact information:
Appointments may be set between the hours
of 9:00 a.m. to 3:00, Monday through Friday. You will need to allow an hour for the interview. You will be given additional information and instructions to bring with you for your
second interview.
"All new applicants must demonstrate they are residents of San Diego County,
have good cause and good moral character, pursuant to PC 12050. For purposes of this application, applicants must submit proof of residency in the form of two current, unpaid utility bills that list their name, service address and mailing address (or other similar type proof).
Three character reference letters are required to assist in substantiating good moral character. These
letters must be written by local residents and contain a local address and phone number. Letters will
not be accepted from any relatives.
The writer must also acknowledge he or she understands the letter is for an application for a concealed weapons license.
Good cause is an individual issue; however, if applying for business purposes, proof that you are a legitimate and fully credentialed business will be required as well as having to demonstrate that good cause for carrying a firearm exist. The same applies for those wanting to apply strictly for personal protection; the required documentation will be discussed at the time of the initial first interview, additional documentation may be requested. Valid California identification is also required."
http://www.sdsheriff.net/mgt_serv/licensing/ccw.html
