The excellent War Is Boring blog did one of their “gun porn” articles on this very subject recently:
They are a very interesting blog on all things military, I find their historical and international relations pieces some of the best reporting out their. Their pieces on the the minutia on some particular variant of gun (which I’d would call “gun porn”), I don’t enjoy as much.
Might just be aesthetic. The gun is made from whatever scraps they had around. It probably has markings from its previous life, rust spots, machining marks, etc. If you’re the machine shop, you want to sell the gun for a high price, but if the gun looks crappy then it won’t sell for as much. You paint it so at least it has a consistent finish. Eggshell white happened to be what they had.
This pic just showed up of a seized weapon. What the hell is it, besides something that looks like it can shoot bullets?
Bump for a new x-ref on this: Why are 3D printers so relevant to plastic gun making?, which here and there refers to this OP general topic, and specifically related to Martini’s post cited here, in #31.
Actually, I don’t really know about the specific technology, and I should have added that the political fanatic cited in the plastic-gun thread probably only named his design “The Liberator” for the original’s mighty fine historical setting and purpose, as opposed to having jack shit to do with the real thing.
Bump. I’m sorry for a second x-ref to a plastic-gun thread, where some of the points here are inevitably made, but a my query on a comment from there more properly belongs here, where the topic is tools and tech for cobbled-together metal guns:
Aruvqan writes:
I forgot about the term/thing “zip-gun.” Is it merely a dated word for “cobbled-together handgun” (:)) or is it some kind of tech genre named, no-doubt, here upthread, but with the step “add elastic band?”
What are its ballistic characteristics?
I grew up in NYC. We made zip guns with automobile radio antennas, obtainable while walking down the street, a barrel bolt, a block of wood, and a few screws. Oh, and a rubber band. Preferred ammo was 22 Short.
The middle East minus Israel. As opposed to the Mahgreb, Arabic-speaking North Africa.
Interesting. I’ve never encountered the term before, although I get the etymology.
So Israel and Egypt are neither Mashreqi nor Maghrebi?
And what about Arabia? (Sorry for this tangent.)
I don’t…
And here you grew up to be a respectable Charter Member of SDMB. 
Not so sure about that.
Egypt is part of the Mahgreb.
New crop here (1/20/20, Times of Israel).
Are all these things functional? I can’t even make out the requisite chambers in some. Plus, they are rusty from storage/hiding, or that’s the way they are (use what you got)?
The ones on the right third or so are mainly parts, it looks like, but the others look to have everything you need to fire at least one round, assuming not-visible springs. While untreated sheet metal will corrode when exposed to heat and corrosive ammo, these look so badly corroded that I suspect some spent at least some time in frequent contact with water. Possibly salt water.
Yeah probably about the rust–seeing that this bunch is arrayed on one piece of blue material, and that the story said 64 Carlo guns were seized–perhaps this was one batch retrieved from water. Just a guess.
