havesomeseichel, you said before that “all bullets for hunting have lead in them”. I have never owned nor used a gun and know nothing about them, but from your phrasing it sounds like bullets that are not used in hunting guns do not have lead. Therefore, if you own a gun to protect yourself and not to go hunting, you should not be affected by this law even if you do live in one of the Dakotas.
Furthermore, if the law only applies to Tuesdays, there is no way the government could confiscate hunting guns. What would they do, force citizens to drop off their guns at an office every Tuesday morning and pick them up again on Wednesday morning?
(I searched the Internet and could find no reference to or information about this law in the first place. Your recollection seems shaky, as you couldn’t remember which state it was. Is there a possibility that you are wrong about this?)