Have you ever noticed that those in favor of prohibition (Drugs, or Guns, or ...) Never bother to look at the historical costs of previous attempts.
Let's start with Prohibition (of the alcohol variety). We know alcohol is eeeevil so we need to ban it. And we do. Then we get - Alcohol which is untaxed, served by business which are untaxed, and run by -oops Organized Crime.
Great, so we took a bunch of law abiding people, turned them into criminals, spent a lot of money, gave serious help to the Organized Crime business. Lost revenue, and we still have Alcohol because it DIDN'T WORK.
Then Nixon declares the WAR on Drugs - because drugs are eeeeevil. Since the beginning of the war on drugs criminals have made Billions of dollars, we've spent over a trillion dollars, we've arrested over 45 million people, and turned prisons in to a serious industry. Net result - more drugs are available to day a lower cost than any time in history - yeah that's working really well.
Then there's the race/class issue of the laws. I just learned this, I was kinda surprised. If your caught with 5grams of Crack you get 5 years minimum, for 50grams you get 10 years. but you need to have 500/5000 grams of powder to get the same sentence. Crack is (much to my surprise) Powered Cocaine + Baking Soda + Water + some time in the oven. So it's basically coke cut with baking soda. So why is the sentence for crack 100 times more aggressive? Primarily because it was viewed as the drug of choice for blacks - although no one is going to admit that.
Given these two informative history lessons - (from which we've learned nothing) Just how do you suppose a ban on firearms would work? Gun running would be come a major industry here is my guess.