Uh, amending the Constitution requires a 2/3rds majority in Congress and ratification by 3/4ths of the states.
Look at the history of the 21st Amendment, which repealed the 18th (Prohibition). It was a long & difficult process even though the movement to do so was wildly popular.
The Second Amendment will never be repealed. And if the government announces, “Citizens, you can’t have guns anymore. You must forfeit them to the State”, there will be civil war.
Of course it does, but we were speaking of states secession, so I only included the state's portion of amending the Constitution.
If you want to complete the civics lesson, there is also the means of a Constitutional Convention called by 2/3rds of the states.