Even if you wanted to, how could you possibly regulate this? Once items get to the point of being able to be easily manufactured in your own house, in mass, relatively cheaply, it's nearly impossible to regulate this away.
Think of prohibition. People can/could easily make their own alcohol in their own house by just leaving grapes in a barrel. It was next to impossible to regulate and required substantial man power to prevent the little they did. Grape juice in the era actually said on the label "Do not leave in a jug for 20 days as it might turn into wine." CNC mills are not illegal, just as grape juice wasn't illegal during prohibition. You're likely to start seeing CNC mills with warnings like "do not use to make firearms."
If you try to regulate schematics, people can just download plans from some P2P service. Now you guns that are made from lower grade materials AND questionable designs.
Yesterday it was alcohol prohibition. Today it is drug prohibition. Tomorrow it will be homemade gun parts. You can try to regulate away these things, but once you can easily make them in your own home, it's a losing battle. Attempting to regulate these impossible to regulate things leads to no-knock raids, death, and more criminals. Nobody is safer and I'd argue we're all less safe. Even if they are illegal tomorrow, 20 years and 1 million no-knock raids later, they will be legal again. Prohibition never lasts.
If more guns on the street is creating a problem, then you need to start thinking about different solutions. Making it illegal to possess a firearm isn't going to fix anything.