As documented in Bill Wiese's AR/AK FAQ, the only AR's and AK's which are "assault weapons" are the ones on the Kasler and Roberti-Roos lists.
Pistols
Although all complete pistols have to be drop-tested, Paradox of Calguns observes that you could finish an 80% frame out-of-state. More details later, if I can get his permission to repost. Thread URL: http://www.calguns.net/calgunforum/showthread.php?p=449329
Large Capacity Magazines
Although it is illegal to import a large capacity magazine across state lines, it's legal to purchase one from a Californian armored car company (and there's some lingering dispute / thought that FFLs may be able to). Check LegalCaliforniaMagazines for more details.