A guy with a rifle is not a threat to any modern Army.
I agree that 1 guy with a gun isn't going to win a war. Hell, even a hundred. 1 guy can however cause a lot of chaos and confusion, and even shut down entire states for days.
Remember that it was just a few guys with rifles that had law enforcement and the general public shitting their pants every time that a loud noise was heard. Dorner had one of the largest police forces on the planet walking on egg shells. The DC sniper had most of new england scared shitless.
really it's a non issue, most of these homemade guns are pretty useless, including this 3d printed one. With a lifetime measured in tens of rounds, it really isn't all that special.
and as always, you still get the same time in the federal pokey if you get caught doing something naughty with it.
If a ban is passed the manufacture of 30-round magazines will be just as illegal as owning one. And the penalties are often far worse! To the tune of thousands of dollars and up to 10 years in federal prison. That's the way that it is now for machine guns and other NFA devices, and the way that it was during the previous ban.
I *could* grow pot and poppies and cocoa plants in my backyard with the intent of manufacturing drugs. This doesn't make it any more legal under current federal law, even if it's only for my own personal use. Still get to go to prison when I get caught.
Some people pray for more than they are willing to work for.