Yes you can but in CA It would be Illegal with a bullet button you need a tool to depress the magazine release but it will still work

Daniel - ARs in CA have to be modified .. have to be equipped with a device that makes the 10 round magazine a 'fixed' magazine - called a bullet button, or other CA approved device. The mag remains attached to the firearm and loads either from the side or the top. . One can not simply take out a 10 round mag and put in a 30 round mag, especially since possession of a 30 round mag in CA is a felony offense.

It is a CA compliant rifle, and magazines over 10 rounds are now illegal in CA, to the question is really moot. . If you an legally have a 30 round mag, you live somewhere other than CA .. and can have a 30 round capacity AR from the start.

Daniel, yes Sir it will. Most manufacturers including Daniel Defense make firearm packages that have 10rd magazines so their firearms can also be sold in state that have magazine capacity restrictions. The firearms are exactly the same but just have 10rd mags included. The firearms will also accept any standard capacity magazines just fine.