This is the same stupid argument of guns. Just because someone has a gun, machine gun or super soaker. Doesn't make it against the law.
The right to bear arms is not merely to guns, but to knives or any object I choose.
The Second Amendment protects the right to keep and bear "Arms". The first few words of that Amendment would suggest to me that the term "Arms" refers to artifacts which are suitable for use as weapons of individual and collective defense. While it might be possible to use a can of silly string for such purpose, it would be an incredible stretch to say it was "suitable" for such use, except in circumstances where nothing better was available. If the term "Arms" were interpreted to mean anything that might conceivably be used as a weapon, the federal government would be unable to impose any restriction or taxes on the acquisition of much of anything. Indeed, how many things can one think of which could not conceivably be used as weapons?
Since the Revolutionary War was fought with "arms" carried into battle by an individual, hauled by horses or aboard a ship that was privately owned, I interpret the "right to keep and bear arms" to include anything you can carry on your person or on any conveyance you own.
Of course, you no longer own your own body - you can't even sell a kidney to somebody who needs one when you don't. However, if you own a B-52 and have the ability to purchase the armament it is capable of carrying, you have the right to do so in my book.