Originally posted by Nesster True enough.
But leaving aside the rifle for hunting/sport, the shotgun, and the pistol... we can't go our and buy a functioning anti-aircraft gun or one of those machine guns they shot out of helicopters in Vietnam, for example. So there's also a definitional problem: can you bear just any arm you desire, or not? And if not, how do you define the limits? Like pornography, we can't just say we know it when we see it. This is how we end up with ridiculous 'assault weapon' definitions (with input from the manufacturers, no doubt), trying to define a limitation.
I believe there are more fully automatic weapons currently owned by private citizens in the country than by law enforcement. In 80+ years there have been 2 cases where a private citizen who was licensed to own a fully automatic weapon has used it to kill someone. I think the number is close to 150,000 real functioning machine guns that are owned by private individuals.
Even if the law allowed for the private ownership of an anti-aircraft gun, nobody would own one. Any AA gun that was capable of actually tracking and hitting an airplane in this day and age would cost more than a house. Take an M61 Vulcan as an example. It is old (Vietnam era) enough that it can be picked up relatively cheap $6.x million and only cost $4.00 per bullet. It has a rate of fire of 6,600 rounds per-minute ..... or $26,400.00 per minute to operate. This cost does not include another $15 million for the tracking computer and mechanical platform needed to actually use the gun. Economics actually takes care of most things. The reason assault rifles account for only .002% of all murders is that there are many cheaper options that can do much more damage. Criminals typically don't invest much money into a gun that they know they will need to destroy or dump to keep from getting caught.
Explosive are a little different simply because anyone with half a brain and some common (legal) ingredients can make very devastating explosives. This is why Afghanistan is such a problem.... not because the Taliban have $24 million machine guns. Way more troops are killed by IED than gun fire. For $50.00 you could make a FAE that would flatten an office building or a store the size of a Walmart.