yeah, the consequences are that the law in question gets overturned.
you're not arguing for enforcing existing consequences, you're trying to make up a whole new set of consequences.
people get extremely emotional about the topic of firearms, so let's take what you're saying and apply it to a different context, and hopefully you can understand how ludicrous it is.
FDR signed an executive order [0] for internment of American citizens of Japanese ancestry. it was challenged in a case that went to the Supreme Court [1].
SCOTUS upheld that executive order as constitutional. but let's imagine it had gone the other way, and been struck down as unconstitutional.
with the "consequences" you're proposing, a decision striking down EO 9066 would also imply President FDR must go to jail, wouldn't it? after all, he violated the Constitution. that is an insane outcome - a 5-4 SCOTUS vote could send a President to jail?
the Constitution clearly lays out methods of punishing elected officials - impeachment and possible removal by Congress. in your zeal to defend one tiny sentence of the Constitution, you're inventing out of whole cloth a completely separate way of punishing elected officials, one which would itself be unconstitutional.