The next change will probably look like this:
Missouri: That the right of every citizen to keep and bear arms in defense of his home, person and property, (*Insert change here) or when lawfully summoned in aid of the civil power, shall not be questioned; but this shall not justify the wearing of concealed weapons. Art. I, § 23 (enacted 1945).
*INSERT: "except on days that fall on Saturday and Sunday in each month and other days that fall on Monday, Tuesday, Wednesday, Thursday and Friday of each week;" (2004)
I think the 1820 clause was sufficient. Who gave gummint the right to question the rights of the people of MO? But then, I think that happened in every state. New Mexico is similar.