Not a lot of technology to rifle a lo-tech gun. The Museum of Appalachia has most of an early 1800’s gunsmith shop with both an original homemade gun drill and rifling machine. Both machines are 90% WOOD!. The rifling grooves were cut by a single-point tool pulled through the barrel by a hand carved high pitch wooden lead screw about 6" diameter x 5’ long. I can’t find a good picture of these devices but I’ve been there.
Sorta found it - bottom picture:
https://wolfshieldforge.wordpress.com/2013/06/28/blacksmith-and-gunsmith-shops/
I don’t really know. I assumed these guns would be used because quality weapons were unavailable. If they can’t use other ammunition, even to extract the propellant then I’m not sure what the alternatives would be. I assume nitrocellulose wouldn’t be that difficult to make, but perhaps a bit unstable. Maybe an aluminum based flash-powder? I’d think hand made black powder would tend to be somewhat unreliable and dirtier than factory made though.
Equal access to both (for the sake of argument) but concealment and transference easier with ammo; which leads to: easier access to markets of ammo.
I recall seeing some sort of educational video on Colonial Williamsburg’s gunsmith, and he had a rig a lot like that- bigger screw cylinder though. After he’d forged and bored out the barrel, he fixed the barrel in one end, and fixed a little tooth on the machine’s rod that was affixed to some sort of holder that rode over the screw cylinder. Then he basically worked the holder back and forth over the cylinder, so that it turned the rod in that exact pattern, cutting a rifling groove into the inside of the barrel.
He moved the starting place of the tooth around a few degrees, and repeated the process to cut more grooves.
Nefario, thanks for the links. It’s low tech but done well.
Update on supply and demand:
Throughout last year, the [Israeli] army shuttered 44 workshops that were allegedly being used to make guns. It is on track to increase that figure in 2017, having closed down seven of these shops thus far.
The IDF’s crackdown has already yielded some quantitative results, tripling the cost of a Carlo-style submachine gun between May and October 2016, the army said earlier this year.
The price of higher quality Carlos jumped from approximately NIS 2,000 ($527) in January-May to its current cost of over NIS 6,500 ($1,700). Cheaper versions of the improvised gun became three times more expensive, from a cost of NIS 1,500 in January-May to NIS 4,500 as of January, according to army estimates.
Sort of related question:
There was a flourishing underground Stengun-production in occupied Europe by resistance groups during WW2. Specifically I heard about some which were made in a danish bicycle workshop. What made me curious was that it said that they couldn’t make the barrels themselves so had to steal them. It seems a bit backward to me, weapon warehouses must be some of the most heavily guarded places in an occupied country, and if there’s spare barrels inside, I should think there’s probably also assembled guns. Can anybody help me with an explanation?
Source (in danish):
http://www.stengun.dk
as mentinoed up-thread, Australia has had a bit of a problem with home-brew sub-guns:
They really aren’t difficult to make. Anyone with very basic shop skills, simple garage tools, and access to a hardware store can kluge one together.
The barrel and integral chamber won’t be made of water pipe, but the “receiver” certainly could be. As this will form the main body of the firearm, it is not wrong to claim it is made from water pipe.
On a blowback firearm, the receiver isn’t substantially loaded at all, it only serves to hold the other pieces in location. At least one modern arm, the Kel-Tec Sub-2000 folding carbine, uses a plastic receiver that is hinged in the middle, and low strength aluminum examples of blowback receivers are quite common place…the Ruger 10/22 probably accounting for the most as far as numbers.
A blowback firearm relies on the inertia of the bolt and follower to contain the pressure of firing, not mechanical strength as with a locked breech firearm.
Even locked breech arms can have a very flimsy receiver if you provide a bit of good steel for the barrel to tie into and the bolt to lock to…the AK gets by with a thin sheet metal receiver because the front tr union block does the work, and the AR can use aluminum receiver due to a similar design feature (can’t recall at the moment what they call that steel ring the barrel screws into)
It is still possible to build a functional gun barrel from scrap, if not water pipe. Decent steel for barrels can be salvaged from vehicle axles, or leaf springs if you have a forge. and drilling a pistol (or SMG) length hole in a largish pistol caliber isn’t especially difficult…gun drills are not needed until you get to carbine length. At typical SMG range/accuracy, you could forgo rifling, but even that is manageable if you are resourceful and determined.
The phrase you were looking for in regards to the AR is “Barrel Extension.” Other firearms use a “Trunion” - depends on the method of lock-up, which you use.
Honestly, for pistol-caliber SMGs, seamless steel piping will do just fine. Rifling jigs are easy to build with commonly-available materials and a bit of knowledge. Or you can just go smoothbore, and realistically not lose much in terms of accuracy at typical “effective” SMG ranges.
I (obviously) won’t point anyone to the necessary plans, but they’re not hard to find.
DISCLAIMER Building an unlicensed full-auto firearm is a serious crime in pretty much every nation on the planet. Do Not Do It! DISCLAIMER
Edit: Ninja’d while feeding my face
Pyrodex is a superior black powder replacement, and a near-copy of that powder is do-able by any competent home-brew chemist. There are sugar-based powders, and even powders that use Iron Oxide (red or black). Nitro-based powders like cordite could be made with some extra effort, but realistically any shop that can make cordite can make more efficient, cleaner powders.
It’s just called the barrel extension. The front of the bolt has matching splines that slide into the extension, then the bolt rotates a small amount to prevent it blowing backwards when the round fires.
http://www.midwayusa.com/product/776862/les-baer-custom-barrel-extension-ar-15-steel-in-the-white
After the round clears the barrel, gas pressure slides the bolt carrier backwards which rotates the bolt and as soon as the splines line up, the bolt and carrier together slide way back to eject a round. Then a spring pushes it forwards to push a new cartridge out of the magazine lips into the chamber.
http://www.tacticallink.com/JP-Rifles-Stainless-Steel-Low-Mass-Bolt-Carrier-Group-for-AR10.html
Dennis
What metal is this recently a seized weapon made from?
ETA, isn’t “seize” a word in metallurgy?
As engineer_comp_geek corrected, but didn’t mention, that’s MOA, Minute Of Angle (or Arc if you’re talking telescopes instead of firearms). Let’s not start another source of confusiopn like the whole magazine/clip thing (another pet peeve of mine).
Yeah, I don’t have a good excuse for that repeated typo. Brain malfunctioned and put As before Os.
Looks like just sheet metal. The paint job in radiator-eggshell-off-white maybe to preserve the element of surprise a second or two longer: it doesn’t scream “gun”.
I don’t think the color is because that was the state of the steel before they worked it - in that case you would’ve seen cracks at the major bending points. But it’s not impossible that they actually made this one out of a residential heater or radiator.
!!
Solves supply problem, I guess, but isn’t that insanely hard to deal with?
Re-working thick (too thick?) metal, bizarro cylinder sizes (or is that simply adapted to?)?