If you put any stock on that makes the shotgun shorter than the 660 cm by folding , telescoping or cutting, you make a PROHIBITED firearm , not a restricted one. We won't get into the Shorter than 660cm with a combination of factory parts because that is in the courts , I believe, so is not decided yet. They only become restricted by the Government /CFC if they are short(under the 660cm) from the factory, when they are being assigned their CFC number. This is probably why the Grizzilys came in with short barrels but over 660cm and the pistol grip was not included/attached. It comes in non-restricted, then depending on the outcome of the court case you can maybe use it legally with the pistol grip.