Re: Benelli M1 Super 90 legal in CA 94550
checked CA DOJ Firearms website appears your gun is good to go. You have the pistol grip but not in conjunction with a folding or telescoping stock 6A & B below. Taken from the CA DOJ firearms website. The website has everything you need to know about selling firearms to CA such as an individual can ship firearm to an ffl without having to go throught the verified dealer program that wholesalers and dealers have to use before shipping guns to CA.
Shotguns
(6) A semiautomatic shotgun that has both of the following:
(A) A folding or telescoping stock.
(B) A pistol grip that protrudes conspicuously beneath the action of the weapon, thumbhole stock, or
vertical handgrip.
(7) A semiautomatic shotgun that has the ability to accept a detachable magazine.
(8) Any shotgun with a revolving cylinder.