The Castle Nut is an item that does not come loose very often, especially if it has been staked properly. However, if it does begin to loosen up, there are much worse things that can happen than simply a loose stock. If the receiver extension rotates too far, the buffer retaining detent will fire itself up into the bolt carrier, and can lock up the weapon. If the stock starts to wiggle, the Multitasker Tool has the ability to get you squared away nice and quick.