Zip guns aren't much of thing anymore, because it's cheaper and easier to get black market guns if you're a criminal. At least, I've not heard about them in the news, nor the term "Saturday night special" lately, because guns are cheap these days. Some yo in the ghetto isn't going to go all McGyver and figure out how to make a gun, if he even could.

Guns are cheaper and more plentiful now for law-abiding types than when surplus military guns flooded the market after WWII. It's difficult to believe, but it's true when you look at where things are at.