People who want a gun, are going to get a gun.
In AMERICA !
In the rest of the world, not so much.

However, you can build a much better, more reliable, more accurate gun that has the same traceability with some simple hobby mills.
You might be able to.
the vast majority of the human race - not so much.
Plus a3d printer can cost as little as $300 - a full on metal work shop and a few years learning how to use it. Way more.

3d printed plastic parts can be made by ANYONE, well anyone who's prepared to learn how to use a gluestick and blue painters tape :-)
There is almost no skill required.
There is no comparison.