The black market ... an amazing phenomenon to say the least. Spawned forth by the entreprising element of society, criminal capitalism at its best and before anything: oppertunism. Given a chance to make bank on a demand artificially generated by government mandate, there are plenty of people willing to risk trouble with mentioned government.
The demand can be for anything. In the Netherlands, smuggling butter was once a very profitable enterprise, much like smuggling cigarettes into the UK these days. Take any commodity, pass a law prohibiting it, and a black market will arise to supply the demand. It was the case when the US prohibited alcohol, it is the case now that many countries around the world have banned certain drugs.
And the black merket, what does it look like? Many may initially imagine a warehouse or similar building with people selling their wares, but quickly realize that is a cartoon image. The black market, it is everywhere. It is the dealer on the corner selling drugs to passers by, it is the appartment out of which a pair of crooks are selling their wares, it are the couriers of a fast-food-style drug delivery service.
The black market is a spontaneously generated organism, whose spores are everywhere and when conditions are met, they settle and grow. An inexterminable lifeform that has no home or ancorage, that has little ties in between, and can remain undetected indefinitely.
In nature, that which grows spontaneously is usually a simple lifeform, but not the black market, and especially not the suppliers to the black market. Recently, we read of semi-submarines used to smuggle drugs, before that, there was the Tennesee pot-cave, there have been many others. With no natural cave, some Britons went as far as to bury eight large cargo units to house an underground (litt&fig) Drug "factory".
The salesmen of the black market and the criminals supplying it are some of the most enterprising people to be found in this world. We will not be able to stop them, even the most opressive regimes have had to deal with smuggling, and often failed at it (underground railroad, the hiding of Jews during WWII) , the black market is eternal.
How can anyone say that we can effectively ban an object? We've spent so much money and effort, shed so much blood to stop drugs, and what do we get? Pot grown in underground shipping containers delivered to your door by what essentially amounts to a pizza delivery service for narcotics.
Do we really want to go through the same mess with guns? I'm not saying we mustn't seek to reduce the damage that gun abuse is causing, I'm saying that a head on prohibition simply will not work.
Didn't work for christianity in ancient Rome, didn't work for alcohol in the twenties, it's not working for drugs, it will not work for guns.