Repeal the second amendment to the Consititution. This would eventually lead to very strict gun control in most States.

This would be a steady but sure way of getting gun violence reduced. Each State would then be able to make laws to regulate and/or ban all guns/rifles and similar weapons. This would happen gradually as each State would respond to the needs of it's citizenry. There is no sacred right to bear arms only a line in the Constitution meant to drive off invaders using the militia, which would necessarily need guns at home when called to duty. There is no longer a need for individuals to own guns. States could pass laws that would severely punish possession if they so choose. Evenutally, after a terrible tragedy, local citizens could eliminate the gun threat or come up with another solution. Also eventually it would lead to a federal ban on most guns/weapons.