my understanding is that the right to bear arms was not intended to be for home security but rather the ability for citizens to band together and overthrow the government in the event of tyranny.
you might think a few guys fighting the authorities is insane and it is but when you have 100 armed people shit gets serious. when there 1,000 armed people you have an uprising. 10,000 there's a serious shit storm. 100,000 and there is a chance of revolution. 1,000,000 and it's time to get a new flag.
so let's see, if 1 in 300 people have a firearm there is enough for a revolution. if 1 in 300 people have 10 guns then 1 in 30 people can have a gun.
no worries though, the US still has centuries before the shit hits the fan. however, when it does, guns will already be outlawed and it will be the weapons taken from killed police and military personnel that are used in the revolution. with the emergence of advanced technology, war will be very different when able people can devise sensory weapons that do permanent damage (blind or deafen). in short, a new kind of terrorism.
"the wisdom of the wise will perish, the intelligence of the intelligent will vanish."