Don't get out much, do you?
Been a massive shortage of everything (except surplus 7.62x54R) for the past year. Everyone has been certain that everything is going to be banned, so they are buying every box of everything on the shelf.
After a bit, it becomes a self fulfill prophecy. We are concerned there will not be ammo on the shelf, so we buy everything on the shelf, so yep- there is no ammo on the shelf.