There were a few things I left out of the video because of censorship, but this is a good place to discuss. The first is the cool story of P.A. Luty. His design is shown in the video, but if you have the time, read
this. Basically, he was an Englishman who designed a scratch built SMG and published the plans to make a political point. Guns based on his design have been seized by police all over the world.
Luty’s clear — indeed, his stated — intent was to make a political point on the subject of gun control. If a firearm could be manufactured entirely from scratch using commonly available materials, then anyone with the requisite skill would be able to bypass national or local firearms law and restrictions on sale.
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The other thing that I couldn't really go into a lot of detail about was the ingenious method of rifling that I just referred to as "electrochemical" in the video. Basically, what IvanTheTroll did was to 3D print a jig that held wires in place on the inside of the barrel, then he passed saltwater and electricity through it to etch away a portion of the surface.
If your urge to know more is intensifying, join the Deterrence Dispensed keybase team
here.