Would it be legal to take a non AW gun,  such as a mini 14, to Nevada and change the configuration to a legal Nevada configuration, shoot it and before reentering Calif. change it back to a Non AW?  Example, take a mini 14 standard stock, go to Nevada and change the stock to a pistol grip stock, shoot it and before returning  to Calif. replace the pistol grip stock with the standard stock. Another example would be to take a M1a with the "Calif brake" to Nevada and replace the brake with a flash hider and before returning to Ca. put the brake back on.  Would the person be in violation of any Calif. laws?  Also one more question, could you keep the pistol grip and flash suppressor in your home, not attached of course.  Thanks for your time!!

No problem reconfiguring the rifle outside of CA and reconfiguring it to a legal configuration before bringing it back in - provided the new config doesn't contravene any state (NV, for your example) or federal laws.

As for keeping a pistol grip - not sure.  My instinct would be to say it's OK, as long as you don't actually assemble them while in Cali.

So, my friend Joe in the PRK calls me up, says he needs some USGI 30's for his AR.  I box up a dozen I pick up at a gun show, and ship them off to Kalistan to him.  The PRK can't do diddly squat to me.  Joe is on his own.  I haven't broken any of MY state laws.

Yeah but CA can bring charges for violating their state laws. And since it was done inter-state, it may just be a Fed offense.