This is at least as deserving of concern as 3d printed guns. The power and accuracy of this prototype implies this really could be the gun of the future. Of course it has humble low power for now. It battery powered, imagine a far more powerful energy source like capacitors or 220V.
It’s energy source is untraceable-electricity. The bullets carry no rifling or distinguishing marks. The ammunition is easily home or shop made. There is no requirement under the law for licensing.
This homemade gun uses electromagnetic coils to send steel rods flying at a speed of 138 feet per second. Pressing the trigger loads a steel rod into the barrel, where the first electromagnetic coil pulls the rod forward via magnetism, then turns off. The next coil is triggered on by an infrared sensor, propelling the rod farther down the barrel, and then so on and so on until the projectile flies out with a thwuck!