Will Missouri "Nullify" federal gun laws?

Amendment X of the Constitution of the United States guarantees to the states and their people all powers not granted to the federal government elsewhere in the Constitution and reserves to the state and people of Missouri certain powers as they were understood at the time that Missouri was admitted to statehood. The guarantee of those powers is a matter of contract between the state and people of Missouri and the United States as of the time that the compact with the United States was agreed upon and adopted by Missouri and the United State

Amendment II of the Constitution of the United States reserves to the people the right to keep and bear arms as that right was understood at the time that Missouri was admitted to statehood, and the guarantee of the right is a matter of contract between the state and people of Missouri and the United States as of the time that the compact with the United States was agreed upon and adopted by Missouri and the United States

I understand the theory behind this. I believe it to be similar to the states that have told the Federal Government to stop overreaching or we will go our own direction. Though my question is does it hold any weight? Will this actually be effective or will the Federal Government just say whatever, we will do what we like?

I am looking at the current trend of states attempting to tell the Federal Government where to go and I find myself questioning if we will have a civil war, or if the states will just start breaking off one by one.