God Bob is a fucking moron.
1) Luty's guns weren't "zip guns". That's not a catch-all term for every firearm produced outside of a major factory. Zip guns are when some jackass duct-tapes a pen tube to a staple gun, or some shit like that. It might work, once, but you don't wanna actually use it.
This is one of Luty's guns.
They may have looked a bit like 80s industrial art, but they were absolutely "real" guns.
2)
There is no part of a (non-full-auto) gun you cannot legally self-produce. That's what scares the shit out of gungrabbers. The only legal restriction on guns you make yourself is you can't sell them or give them away - they have to remain yours.
3) You do not need a "machine shop". That's one of the things Luty set out to prove. You can make a gun with the contents of a modest garage work shop like millions of households in this country have, and a bit of time.
4) I know this isn't Bob making this point, but "Village of the Dan'd" is also a moron: Half of the guns made today are "plastic". Industrial polymer, really, but "plastic" all the same. The most popular pistols in the world right now, Glocks, are the poster child for "plastic guns". Even AR-15s are made of lots of polymer. There's only a couple parts that can't be made out of some sort of polymer... The barrel and firing chamber, springs, the firing pin. We make the slides out of metal mostly for weight to make the recoil more manageable, not for strength.
Gun grabbers wouldn't bother me so much if they weren't always so fucking ignorant.