"Junkyard Wars" Semi-Auto Rifle(?)

H

Higgins

New member
Okay, you've been asked to be on "Junkyard Wars" (you know, the tv show where two competing teams enter a junkyard and are given 10 hours to build things - like a dune buggy, or a rocket, or a submarine, or a small artillary piece, etc....).

Anyway, when it comes your turn, your team is told to come up with a Combat/Assault rifle. So, you've got 10 hours in a junkyard with only the materials you can scrounge and only fairly basic electric tools/welding supplies (no lathes, milling machines, etc...) and you have to come up with a working combat/assault rifle. (Assume the ammo, any kind you decide upon, will be provided - you just have to come up with a working rifle, not the ammo).

What's your plan/design?
 
if they can make an AK in Pakistan in a tent
then in a junk yard with an arc welder should be do able

but i want Marc Krebs on my team!
 
Weeel, .....John Browning hung a tin flapper out beyond the muzzle of a lever action and used a portion of the muzzle blast to actuate the lever. Buildin a lever action in itself a little complicatedly sooooo.......I would use John's daddy's idea of straight crossways block full of holes with cartridges in it, then ratchet the block sideways with little John's muzzle blast flapper thingie. Easiest to do with junkyard parts maby use shotshells. Low pressure slug loads like Aguila Minishells. Whatever fits a good piece of tubing fairly well. Use the tubing for barrel and as breech block inserts.

If the referees are picky bout rifling....use seamed tubing for barreland put a twist in it. That would give single land rifling. Slip another tube of next larger size over the works to help keep it together when it goes bang.

Could do an eight or ten shot one without gettin too bulky.

Interestipating, gotta go look in the junk pile out back.

Sam......been weeks since I blowed sumpin up.
 
Never head of the show.......... must be on cable......

Well, there goes my idea for a shotgun. Two pipes and a nail.....

Semi auto.......hummmm............

Well, it wouldn't be 'accurate' w/out a rifled barrel..........
 
Well i have seen the show, and from what they have to make things out of, and the tools they have, i think the best gun for them to make would be a Sten gun.
And yes i know it's not a rifle, but it's the only Semi-Auto (Full-Auto) gun i can see them making.
 
I think the hardest part to manage would be a magazine, but if you can use a "hopper" feed system, it would be feasible. I've seen a couple of firearms that were made entirely IN PRISON, and you'd be surprised at what can be made with some pretty plain-looking junk. One of the most recent I've seen used 3 flashlight bulbs as an ignition source, with the battery in the grip, and three aluminium "barrels" cast into a resin body. Pretty bizarre stuff.
 
An unrifled barrel, compressed gas shooting round ball - simple vavling. The hard part would be limiting to semi as it would be full till the gas was shut/vavled off.

Or, one could specify that the junk yard be in one of our Aussie friend's back yard. I hear there was quite the pile of available parts ..... :(
 
wow.. sten gun was the BEST answer.. yeah i know you can make an ak in a tent but... I'd end up with a 22 cal zip gun (with a silncer naturally) thats a pretty damn effective little 'assault rifle"
 
Okay, the general sense seems to be that creating an assault/combat rifle under "Junkyard Wars" conditions, i.e. 10 hours, hand tools, only junk to pick from would be pretty tough, if not impossible. (I note however that Bill Holmes of the Home Workshop firearms series of books always mentions that a junkyard could be a good source of parts - e.g. truck axels as barrels, car sheet metal for receivers, etc... for homemade firearms, and he makes everything from 50 cal sniper rifles to full auto submachine guns to handguns.) But apart from that . . .

. . . Let me pose the question in a slightly different manner. Forget about the Junkyard Wars limitations. No 10 hour limit, not limited to just a junkyard for materials (but no gun kits or already made firearm parts), and have access to slightly better tools/equipment (e.g. electric drills, grinders, arc welder, but still no advanced equipment like milling machine or lathe).

If you had to come up with a combat/assault rifle on your own, with access to suitable raw materials (sheet metal, suitable barrel material, aluminum, wood, plastic, ... whatever) but with limited tools/equipment - what design would you try to copy/follow?

Imagine any situation you like where you might need or want to do so. Like DZ mentioned, imagine you live in a tent in Pakistan or some other remote area, or the SHTF and you need a rifle but can't buy/steal/find one, or hell, you just happen to be a hobbyist and want to try your hand at coming up with a workshop/improvised combat/assault rifle.

What design would you try to follow. Again, ammo is not an issue. (I know Sten would be the obvious easy firearm, but I'm more interested in what combat/assault rifle or method of operation you think would be the easiest to copy/recreate).
 
I'm with "dude" where the design I'd try to duplicate would be a STENGUN, M3 Greasegun, or Swedish-K .

Maybe not a rifled barrel or anything overly complex, but hell I wouldn't even go for semiauto because I'd need to rig up a disconnector system. Just go for an open bolt submachine gun and chamberings would depend on whether or not you could or could not ream out a chamber with ease or find suitable barrel material for anything over 22lr. I would also figure that the barrel length would be extremely short so that it would make it easy enough to drill a hole through a piece of steel then ream it out, reaming anything more than 2-3 inches in length would likely become difficult for hand tools or wouldn't be a standard procedure that could be very easily accomplished without proper machine tools. I'd think that it would be possible to make a crude bolt to work in an open bolt fashion, the magazine would definitely be the hard part but it could certainly be possible to make a hopper setup that used gravity feed to let the bolt strip rounds from it and into the chamber.


The shotgun concept has merrit too, heh, why not go for a 12 gauge gatling gun where all the barrels are just smooth bore with a gravity fed hopper? Would take somebody who is very familiar with the older gatling gun designs but I would think that it could actually be done with todays handtools which are quite decent compared to the tools of the older days.
 
I think I saw in Guns and Ammo magazine

a home workshop .50 BMG rifle instruction (you know the ads where you can get yourself a copy of Art of the Rifle and The Ultimate Sniper). Anyway, I don't know if the guy could build it in 10 hrs but it definitely would be an interesting gun to have. And if you were forced to use it in a no-win situation (the only way I could see a sane person wanting to use one), you wouldn't have to worry about being taken prisoner if it blows up. Another bonus is if it fails you probably could take out some of the enemy with you.
 
Mortars would be a piece of cake. There are drive shafts which have an ID the same as the OD of a beer can.

Drill a hole about a foot from the closed end. Use a nail or piece of wire as a stop to control how far in the beer can goes.

You have to work up the proper oxy-acetylene mix as the propellant charge, introduced through a small hole below the beer can via a #2 welding tip.

Now, this rig was known to launch a full can at least three or four city blocks. This was at a buddy's filling station in Fort Lauderdale back around 1960 or so. "Last seen still rising across Sunrise Boulevard!"

:D, Art
 
Art......you just made my ears ring even worse than normal. Oxy-Acetyline canons, morters, balloons, trash bags etc have been wonderfull toys since OSC in the early 50s to present. Rearrange garage, remove drywall, clean store windows, insert billard ball in Porsche, put oleander bush in orbit, cure peach leaf curl.

Even built a multi barrel repeater but it required a bunch of high dollar valving.

Sam.....boom is good, BOOM is more gooder.
 
If we're talking a given type of high pressure rifle bullet ammo, a recoil locking system as used in machine guns like the Browning M2 or the Johnson rifle of WWII might allow the sloppiest tolerences.

Some form of gas delayed blowback (P7, GB) might also work as neither design calls for precise interaction of bolt and barrel.

Also something of a gyrojet type rotating design (gun design, not ammo), with a two part chamber and barrel that is driven forward by gas pressure. That might address feed device concerns.

Blow back with an oil hydralic delay using auto strut valves.
 
Not wierd enough. How 'bout this. A 10 0r so chamber bored cylinder, with a standing breach. Zig zag cuts on the outside of the cylinder. Out to the end of the barrel a hole and a angled port. Into that a rod with a cup (in a tube carrier with a spring-affixed to the barrel) linked to the cylinder. It fires, the gas kicks the rod back, rotates the cylinder. Could likely cock the hammer by linking to the backward movement of the rod. Problem is that couldn't eject empties. And would be very sensitive to the power of the cartridge. Or just a bit likely to blow up. Anybody got a tig, some die grinder and some pipe and odds and ends?
 
Oxy-acetylene, to get the perfect mix just adjust to a neutral flame w/ a large rosebud or welding tip. Snuff out on bench and proceed to filling. It pays to note that old style glass coke bottles come with their own free rifling and readily fit standard pipe sizes. A 50 gal trashbag full of oxy-acetylene is also something you should warn the neighbors about. As far as the improvised weapon it looks like you have to stick with straight-wall cartrides for production ease. My assualt rifle from junk would only be good enough for one BATF disapproved, carefully planned shot. My second shot would come from my newly aquired one-owner M-4.
 
Y'all are missing a killer source of powerful compressed air pulses which could be timed with a mechanical pellet delivery system.

Yep. Take a truck V8 diesel engine, take the hotplug out of one cylinder, use that cylinder to power an air hose attached to the back of the barrel, run the pellet delivery off the crank via belt. After that, just basic mechanical timing and calculated gear ratios.

OK, now for a truly weird alternative. Use any running engine, at least a four-banger car motor or better. Set up a thing on the crank that "flings" ball bearings via centrifugal force :D. You'd feed the balls in at the center of the crank and a curved steel outwards-pointed ramp, sorta like a LaCrosse paddle or whatever they call that thing. Now, "aim" would be a matter of which point in the rotation your auto-feeder puts the bearing, coupled with RPM. You'd need to *precisely* control RPM but that's not a problem because many electronic ignition systems feature a cut-off at redline - it's called a rev limiter. Use that to precisely keep it wound up. Once spinning, feed it balls and see where they go - shorten the launch ramp to control rough elevation, put the whole motor on a tilt'n'swivel for fine aiming. Rig the pellet feeder to the crank timing again...

6,000 rounds per minute should be easy enough to get :D:D:D.

Can you tell I'm an old hot-rodder? My brother and I once got his '82 Toyota Supra up past 160mph, we edged past a Ferarri 308GT at 2:00am on the freeway :).
 
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