It has been known for decades that guns are easy to make at home. The hard part is getting the tools and jigs and set up. Anyone remember the FIREPOWER MAGAZINE from the 1980s?
The Polish Underground in WW II used homemade sub machine guns against the Germans.
Same in SE Asia in the 1960s.
https://homemadeguns.wordpress.com/2014/08/01/homemade-semi-auto-pistols-part-1-vietnamese-copies/
https://www.forgottenweapons.com/viet-cong-handmade-luger-lookalike/
I remember an article in GUNS AND AMMO magazine back in 1970 talking about the problems of semi-auto guns, and ammo, being made, by prisoners, behind California Prison walls.
Interesting specimens...
Brandon Herrera on youtube points out that until now, in the history of our nation, its always been your right to build your own firearm without government interference. These bureaucrats have no shame.
https://m.youtube.com/watch?v=kf0BCpns31s