Remember that the Founding Fathers provided in the Constitution (Article VI, Clause 2, emphasis added):
Printz v. U.S.
This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby; any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.
, 521 U.S. 898 (Supreme Court, 1997) ruled essentially only that a federal law could not direct state law enforcement officers to participate in the administration of a federal regulatory program.
But the federal government may still administer its regulatory programs in a State. And if something is illegal under federal law, it is still illegal even if it is not illegal under state law. So you will get arrested by the FBI, ATF, U. S. Marshall or DEA, instead of the local police or sheriff; you will be tried in federal court instead of state court; and you will go to a federal prison instead of a state prison.