I'm just using yours as a basis quote, TSC. When I was 14 I issued a "Special Weapons Permit" for our camping club when I heard that some members were shooting at each other with BB guns -- and popping the BBs back out of their foreheads; they'd shoot into the bushes without even knowing what, or what part of what, was in the line of fire.
People tend to think of the U.S. as one big country with all states under all-encompassing mutual laws. Not so -- each state has an amount of sovereignty within their borders. In fact, when the federal 55mph speed limit was issued by the federal government some states were slow to comply. Nebraska only did so after the federal government, to force compliance, refused to return any assistance (money for construction, road repairs, etc., from accrued taxes). Not all laws, therefore, are uniform.
Since the federal constitution has a clause on "the right to bear arms" and it is agreed that it does not refer to the appendages dangling from the shoulders, bare or elsewise, totally banning weaponry is not likely. "All men being created equal," there is also no definitive recourse for those who remain or become stupid; many of these will either bare or bear arms (sometimes both -- and it is difficult, when not impossible, to bear arms with no arms).
To my knowledge, it is illigal in most states for 'convicted' felons to carry firearms. Specifics, howbeit, can vary in each state. In New Hampshire it was legal carry a gun as long as it was not concealed (biological variants are not subject to that law, Foz, et al). Some of my schoolmates actually made their own guns in shop class (without the instructors knowledge); one of my classmates even made his own mortar. In that respect, guns can be obtained even if manufacturing them were illigal (shades of "Prohibition').