Not to mention cannon. At the outset of the Revolution, many cannon were privately owned. Privateers had private canon throughout the Revolution and the War of 1212. While one can still own a Revolutionary war type canon, the second amendment does not say the guns had to be of a 200 year old type.
Good addendum. If the founders wanted to limit the 2nd amendment, they would have said the right of the people to keep and bear arms shall not be infringed unless they are cannons shooting projectiles larger then the 6 pound variety. It sounds funny to us, but that is exactly what our founders did with the 4th amendment. They limited it.