Saiga 12 question.

I'm looking to buy and modify a Saiga here in Ca and was wondering what rules apply.I intend to shorten and muzzle-brake the barrel to 18", change the furniture and buy a "parts kit" drum for dexterity.I've read there has to be a certain number of American parts on it to stay 922r legal.

Any help is greatly appreciated.

When finished it will look something like this...

my bad, mods please move to og.

why was i not told about!