You know, I recently saw a benelli m2 semi with a pistol grip for sale in a gun shop in NJ, which shall remain unnamed.
I asked about it, and the owner stated that most people dont read or know the law and it was perfectly legal.
All I could think of was getting a rifled slug barrel for it and making it a bear/deer gun...
So I looked it up. (I should have known better, as a reputable gun shop knows what he is doing)
As long as the guidelines are followed, as set out by the AG in 1996, a pistol grip is ok, as long as the gun:
Does not have a telescoping/folding stock
Take more than 5 rounds
Be able to take a detachable mag.
If you only have one feature (a pistol grip) a semi auto is OK and NJ legal.