A semi-automatic design of homemade gun with many chambers

M

Monday

New member
Hello, i made a design of a simple gun with a firing pin for every chamber.

It look like this: http://imgur.com/download/BqYQzfa

It's a multishot version of a "pen pistol", it's basicaly many pen pistols put together in a row.

If i would use singel barrels (with a thickness of, for example, 8mm) instead of the chamber in my design;

like this: http://imgur.com/download/T4b9pxL

It will mean that i got 16mm walls between each bore, instead of 8mm. So in order to make the gun as compact as possible, without making the walls thin, i made a "chamber" design instead, like a revolver chamber but flat instead of round.

And the chamber design required a different solution of the "firing pin chamber" to, which i show in my first sketch.

With a ordinary pen pistol you simply but the barrel into a pipe that fits it, usually you screw it in place to fix it. But you can't do that with my chamber, so i made a box instead which will hold everything in place.

What do you think about my design? Is it good? Will it work? Do you got any ideas or better solutions for my project?
 
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It doesn't appear that this firearm would be a semi-automatic per se, since there is no mechanism to automatically extract the cartridges and reload each chamber. This design seems more like a novel interpretation of the pepper-box or volley gun concept—the multi-shot capability is provided by multiple barrels and chambers that must be manually loaded, rather than with automatic reloading capability.

I think that a few legal cautions are in order.

If this firearm is shaped like a box rather than a rifle, shotgun, or pistol, and you're in the United States, it will be considered an Any Other Weapon under the National Firearms Act (NFA); you will need to obtain the appropriate tax stamps before building it, and I would recommend verifying that it is legal to possess under state and local law, as some localities prohibit the possession of certain NFA weapons even if the right tax stamps are obtained.

Additionally, if the weapon can discharge more than one shot with each pull of the trigger, it is considered to be a Machinegun under the NFA, and the civilian NFA registry for new machineguns has been closed since 1986; it is a serious federal crime to make a new one unless it is for military or law enforcement use. Be cognizant that the term "machinegun" in the NFA does not only mean full-auto; pay close attention to the wording of the legal definition:
The term “machinegun” means any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger.
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The definition isn't limited to multiple shots coming out of the same barrel sequentially when the trigger is held down; the definition can also encompass a firearm with multiple barrels that fire simultaneously with a single trigger pull.

There is an exception in the NFA for a firearm considered to be an Antique, but in order to qualify for this category, it cannot fire a readily-available fixed cartridge such as .22LR.
 
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Yah, it's more like a volley gun than a semi-auto, but you do not shoot all barrels at once, like a machine gun, instead you shoot them as a semi-auto, but with a unique trigger for each barrel.

Like this: http://imgur.com/download/FmaZ7B0
The middle barrel is fired
Parts of the gun: http://imgur.com/download/GCxFuGu

This gun is legal at my location.

So, what do you think about the design itself?

The "box" that will hold the gun together will look basically like this: http://lil.law.harvard.edu/talks/awesome-slides/cardboard-box.jpg

Like a box without any top.

You have to put the parts of the gun down the box, from above, and they will fit snugly into the box. Maybe i should use some kind of band or ductape in order to hold everything together after put in place. They could also be glued in place, but then it will be hard to disassembly the gun.
 
Do I understand correctly that you want to build a multi-barrel gun that stays together with cardboard and duct tape?
 
No the cardboard box in the picture only illustrate what kind of box i mean, a box without any roof. It was a bad example image..

The box i need has to be solid in order to hold everything snugly in place, which a cardboard can't do, and the box has to be of the right dimensions.

As i said, it should fit snugly, and the springs of the firing pins will lay/push at the rear wall of the box, but maybe some kind of band or tape could be an extra support, to hold everything in place from above.

Edit: it could be secured with an overlapping lock, like a matchbox https://img2.cgtrader.com/items/73774/29a642f27d/matchbox-3d-model-3ds-fbx-blend-dae.jpg But then the loock need to have a window for the bolt action of the firing pins, and i think tape will do the work just as good, just to keep it in place.

A matchbox lock of the correct dimensions could overlap this gun, only for the appearance, make it look like a matchbox, very stealth.
 
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What is your overall intended purpose for this gun? 22LR is not a highly effective "man-stopper" even though I know it has taken many lives. It would be hard to hold such a small gun and shoot accurately. Before you invest the time and money into building something like that, you should be able to answer yourself:

What is its intended purpose (and would it be legal)?
Who would buy it and can you make money off of it?
What is available on the market that can do the same thing, possibly better?
Would it be reliable?
Would it be dangerous to the shooter?

For me, there is no shortage of very small pistols in effective calibers on the market. This includes proven designs like the Beretta flip up barrels (Jetfire, Bobcat, Tomcat), Seecamps, etc. Some slightly larger, but still highly concealable pistols are on this page: http://blog.cheaperthandirt.com/top-15-smallest-pistols/
 
It might not be apparent in, say, .22, but any larger caliber will pretty well show ithe disadvantage of having 5 barrels, five firing pins and springs, a wide box to contain the "thing", etc. And one in .45 caliber would be pretty heavy, not to mention bulky. And to what advantage? Why would I want to buy that gun instead of a normal 9 or 10 shot .22 or a 6-7 shot .25 Auto if size is the big factor. And of course, you will need some kind of mechanism to actually fire the gun, more to the next chamber, etc.

It seems to me that the only advantage is that when boxed up it might not look like a gun, but that means little. Any cop searching a suspect for a gun won't ignore a heavy, bulky box in the suspect's pocket just because it doesn't look like a gun.

Jim
 
I don't see any triggers or anything to fire the gun. Do you just push the firing pin forward? Thinking a cardboard box, tape or a rubber band will contain the blast of a .22lr seems like wishful thinking if not downright dangerous.

This makes the NAA mini revolver look like a work of art.
 
reddog81 said:
I don't see any triggers or anything to fire the gun. Do you just push the firing pin forward?
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Other than the structural integrity question, that was my primary question as well.

As I discussed previously, U.S. federal law effectively prohibits the construction of a new multi-barrel gun that fires .22LR volley-style with a single trigger. The gun will require either individual triggers for each barrel or a mechanism to allow a single trigger to fire each barrel sequentially. Additionally, if the gun uses pre-cocked strikers, it will essentially function as a single-action and some sort of safety mechanism(s) will be required.

IMHO these mechanisms pose a greater design challenge than the barrels or frame themselves, and are therefore critical to thoroughly think through.
 
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The gun has individual triggers for each barrel, and each firing pin has to be cocked. You cock the firing pin through each trigger. It's like a bunch of single action pen guns in a row.

Like this, pen gun x5 http://imgur.com/download/0DUcUT9

So it's not a complacated gun at all, my goal behind this gun is to create a reliable basic gun that is very easy to understand, shoot and build.

The only difference with my design and the "pen gun x5" in the picture above, is that my barrels is stuck together, just like a magazine/chamber of a harmonica gun http://www.oddities123.com/wp-content/uploads/2014/02/harmonica-6.jpg

The reason behind that, is to keep the gun more compact, but at the same time to keep the walls of the barrels thick.

This is what i'm talking about: http://imgur.com/download/NmHnJ92

If you build a gun with very thin barrels, my barrelchamber design will not make any big improvement, but the thicker the barrels are, nevertheless important will the chamber design be, based on simply mathematics..

And i will use a wall thickness of 8mm (about 0,3inch) for this .22 gun, so with the chamber design i can add extra barrels without makeing the gun bigger. And i want the gun to be as compact as possible, with as high shot capacity as possible.

But when the barrels are stuck together, as in my design, the "chamber"/"body" which hold the firing pin and the spring inline the barrel, won't be able to do that individually, like it would with a ordinary pen gun.

So i need a chamber for the firing pins also, which hold them all and keep the firing pins inline the rims.

So the barrelschamber and the the chamber/body which house the firing pins and springs, will basically be of the same dimensions, except that the "bores" of the firingpinchamber has to be bigger ofcourse; to contain the spring, firing pin and especially to be able to strike the rim of the .22lr. (The firingpinchamber will be slightly longer to, in order to contain the spring, since i will make the barrels short)

But the barrelchamber and firingpinchamber has to be attached to eachother, and that's where the box gets involved. The point of the box is to keep the gun in place.

The box will need to have the right dimensions that fits the gun, and keep the gun inline, and it will be made out of steel, not cardboard..

My thought about the tape is just to hold the gunparts (barrelschamber and firing pinschamber) attached to the box, from above. So the tape won't hold any recoil forces.
 
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Well, yes, if i would use individual barrels the diameter would be around 2 centimeters, the dimensions would look like this:

Barrel wall 8mm (millimeters) x2 = 16mm
+
Bore 5,7 mm
=21,7mm

So if i have 5 barrels it will be 21,7 x 5 = 108,5mm. So about 4" overall

With my chamber design, the thickness between each bore will be 8mm.

So, 5 bores 5,57mm = 27,85mm + 6 walls 8mm = 48
= 75,85mm, about 3" overall

One inch shorter with the chamber design, which is a pretty big difference when it comes to small compact guns.
 
I'm not trying to dissuade you, but what problem does this solve that is not available on the market today? Like I said, .22 LR is not a very powerful cartridge. The small size of the gun would make operating it very challenging. Hitting anything with it at more than a few feet would also be very challenging due to the short barrel length and lack of sights. Since you are firing out of multiple barrels, each shot would require a slightly different point of aim. If I could only conceal something very tiny, I would rather be armed with a larger caliber derringer that could end the fight quickly. https://bondarms.com/
 
Monday---you have an inventive mind, and I certainly would not want to do anything to
discourage that inventiveness. However--you might want to learn a bit about what has
gone before. I know of at least one firearms encyclopedia available for free Kindle
download. If you have the funds, pick up a copy of Firearms Curiosa by Lewis Winant.
Pretty much every weird design you can think of is in that book------

Your current design has elements of stack barrel pistols with a bit of harmonica gun.
 
Look up cell phone pistols and you will see basically the same thing. Also saw one somewhat like that made into a cigarette pack.
 
It is a NFA design and to even build it will require licensing and tax stamps. (it doesn't meet the requirements of a pistol and is therefore an AOW)
It is not a semi-auto, it is closer to an in-line revolver except you have individual "triggers" for each chamber. It will be difficult to have any accuracy at any range and it needs a handle to hold on to the darn thing. I have designed a lot of guns before but accuracy was always in the forefront in my designs. Multiple barrels are best used in rotary Gatling guns or full auto chain guns.
 
ShootistPRS It is a NFA design and to even build it will require licensing and tax stamps. (it doesn't meet the requirements of a pistol and is therefore an AOW)
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No license is required to make any firearm unless you are engaging in the business of manufacturing firearms. Thousands of firearms are made every year by hobbyists. for their own use.
Only a Form 1 to make an NFA firearm would be required. $200 tax stamp.
 
No license is required to make a short barreled rifle? or a zip gun? or an automatic rifle? (full auto)
It is not only a federal crime to make those weapons it is also a state felony as well in my state.

I am free to make any gun that it is legal to own - any non-NFA gun.
 
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