Home made “guns” are nothing new.
In the 1950s the big worry was teenage gangs making “zip” guns. Do a google search.
The world did not come to an end.
At the time you could order guns by mail, or go to most hardware stores or even some department stores. Guns were easily available.
Mass shootings were rare.
You do not solve societal problems by restricting constitutional rights.
No, but the government and its agents can accrue considerable power and money by doing so.
My dad gave me my first shotgun when I was 11. He bought it at a hardware store.