As cyphertext said it's too hard to swap back and forth, but if you live in NJ you can't legally swap to the adjustable anyway. Perhaps just leave the adjustable stock in the safe (unpinned) just in case you ever move out of Jersey and then you can do the swap back to the adjustable stock. Swapping one time is not a huge issue, swapping back and forth all the time is an issue as said by cyphertext. Not talking legal wise, just talking physically swapping it with all the parts etc.

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Still carrying my S&W 642