Unless the rifle was registered in CA as a CA "AW" prior to 1/1/00 and you are bringing it back into CA after a temporary stay out of state, it is illegal to bring any AR-15 into CA.  The only possible exception would be for one that is configured permanently as a single-shot (i.e. no magazine well).

You CAN apply for a permit to import an AW into the state, supposedly under Section 12230 of the Penal Code.  The language of 12230 mentions "machine guns" but not "AWs" (i.e. it hasn't been technically updated to reflect "assault weapons").  I have no first-hand information about what kind of experience people have had with the application process.  My knee-jerk reaction is to say "Lotsa luck, they'll never issue one, you are totally SOL", but that would be dishonest.

Here's the phone number for the California Department of Justice.  I suggest you call and ask them about temporarily bringing your rifle into the state for recreational purposes.  (Hey, if nobody even bothers to ASK for a permit they surely will never issue one.)

See [url]http://caag.state.ca.us/firearms/[/url]

And call (916) 227-3694 for the "Special Weapon Permits" section.  You may be a pioneer.

Let us know what they tell you!

The only way you can temporarily bring an "assault weapon" in to California is for use in a sanctioned competition. Watch out for the magazines though.  I don't think there is an exemption for any with a capacity over 10 rounds.

New Jersey, you're ok if is 100% post-ban.  You might be required to get a "FOID" card (Firearms Onwer's ID Card).  See the "NJ Concealed Carry" link at the bottom of  [url]www.nationalccw.com[/url] and then at the bottom of that page are links to NJ's ass-gun laws.

Oh yes, mags should be blocked to 15 rounds by putting a small wood block inside the floorplate.  No one's ever asked to see my blocks, but I wouldn't want you to be the first.

Have a good trip,
Norm