Maybe this is hard for you to understand, but you can 3D print firearm receivers on your kitchen counter with a $300 printer and a few dollars worth of material. This isn't the 1800s anymore when making a gun yourself meant you had to be named John Moses Browning and have a full machine shop just to make single shot and lever action rifles. Hell a German guy came up with a semi-automatic carbine design that doesn't require any parts you can't get from Home Depot. I would say it's way easier to make your own gun than to make your own cocaine and heroin, but no amount of legislation has made cocaine and heroin go away.