According to this page (damn it, I can't post any links yet, I'll obfuscate it):
w w w .njguns.com/define.htm
.. the relevant part says:
w. "Assault firearm" means:
[snip...]
(3) A semi-automatic shotgun with either a magazine capacity exceeding six rounds, a pistol grip, or a folding stock.
NJ is the worst...
Man, I do love those pistol grips. New to the forums, just got myself a Benelli M2 tactical a few weeks ago, but with the standard stock, because I live in f**&*% NJ and the pistol grips are illegal (makes it an "assault weapon" - sheesh). Damn wimpy liberal state. But my M2 still kicks butt. Nobody better try any of that zombie stuff on my house late at night!