All of this is mad but I really don't get the constitutional argument.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
It seems pretty clear to me that in the early days of the country they added this amendment to afford more protections to the states to prevent federal over reach or foreign invasion. Basically, rather than each state having an army, they could have well regulated militias and for this they needed to be armed.
So anyone can own a gun or guns as long as its for the purpose of maintaining a militia whose purpose is defending the state or defending the country but at a state level.
There could be a weird argument that you are a tiny militia and therefore allowed to defend your house (though even that's not necessary to the security of a free state) but one person, with no oversight, owning 14 guns, hardly seems well regulated.
In fact, no matter your interpretation of what a militia is or why it's needed, it's hard to argue that any of this is well regulated.