Pesky Constitution
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.
Why didn't the founders also pontificate about automobile and aviation amendments? Because they didn't know jack shit about them. They only wrote about what they knew at the time.
And if you had more than two brain cells to rub together you would have read where the Supreme Court ruled that you could outlaw a sawed off shotgun because it had "no foreseeable military purpose". So the Supreme's realized that the 2nd is about military weapons.
Yet they were used very effectively by tunnel rats in Vietnam. Go figure.