Does a stock/grip change constitute a permanent modification to an AR or other horrible bad bad gun? For instance wouldn't using a California legal non-pistol grip stock on an AR be just as permanent as replacing a thumbhole stock on a shotgun with a non-thumb hole stock? Combined with other changes (no flash suppressor, telescoping stock, etc) could the AR be modified so it doesn't have to be registered? On the state site under the modification Q/A section about registering a gun that no longer has "assault" features
"No. If you modify your gun so that it is not an assault weapon, you do not have to register it. The modification must be permanent however. This includes, for example, removing the bayonet lug by cutting or grinding, grinding off the threads on the barrel, removing the foregrip so that it cannot be readily reattached, or any change that cannot be reversed through reasonable means." Just thinking out loud and fishing for opinions.