It's precisely law-abiding citizens who want high-reliability, higher-accuracy firearms. They want the full advantages of modern commercial cnc manufacturing tech, modern heat treating tech, and sometimes cryo for barrels: for reliability, accuracy, durability. Criminals don't care so much. They're not putting hundreds of rounds (sometimes more) per month through their firearms.
That was the point I was trying to make.
This is just one more easy way to make a gun that will work long enough for you to do your evil deed. What is the point of gun control if something like this is so easy to make?
Anyone can have an AR15 upper, LPK, buttstock shipped to their house. Print a 3D AR15 lower, add a 30 round mag... Heck, someone could do that in California right now and the authorities wouldn't likely know until you have another massacre on your hands.
A criminal or psycho like James Holmes could make his own AR15 and kill plenty of people with a home made gun... Heck, criminals sometimes don't even fire a shot. You could rape a woman or rob a bank with a crappy gun that never fires a shot.
Unfortunately, politicians do not realize that criminals will always get access to guns if they want. Heck, sometimes the US govt will just give criminals guns (fast and furious).