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?
Arms merely means a weapon. And yes, Gov’t cannot restrict such. Having a weapon is not against the law. If I choose to use a slingshot, sword or super soaker, so be it.