.22 Minigun

[ST]

Tried to think one up, but proved to be too hard.
Got as far as the picture above, its run via a starter motor, power is given to the motor the solenoid engages the cogs together and moves the firing pin forward.

The barrels are now spinning so when the cartridge reaches the firing pin it trys to force its way underneath the stationary firing pin, compressing the rim and firing.

I couldn't really figure out how to eject nor load the cartridges, as it would be moving too fast. Don't know if it would work but if the firing pin was on a strong spring ( top right pic) the pressure inside the barrel might bend it back as its fired and blast the spent shell out, where its deflected out to the side..

Anyone think up a way to load such a thing?

Sorry if you came in under a cool title expecting a good post, but i'm mostly posting this to see if the host will allow outlinked pictures...

[nbk2000]

The picture shows up fine.

I've got a bunch of scans from a book about the gatling gun that shows the operation of the mechanisms for firing, loading, drums, etc. It's being included in the heavy weapons section of my PDF.

It's really quit ingenious how Gatling came up with it to make it work. He even made an electrically operated version at the turn of the century that fired 3,000 RPM. The army didn't see any need for it at the time. HA!

An internet search using "gatling AND gun" will result in plenty of material to peruse through. Try "gatling AND video". ;)

[BoB-]

All I found patent number 36,836 "Improvised revolving battery gun" Title; 89/12

Fucking long links, I tried to post a direct link for you but it got screwed up, so just go to uspto.gov

[ January 11, 2002: Message edited by: BoB- ]</p>

[ST]

The first link for a search for gatling AND movies actually gives movies of how it works is that why there is a ;) in your post NBK :)

<a href="http://www.gatlinggun.net/" target="_blank">www.gatlinggun.net/</a>

Its not backyard simple, but still simple design...... but uses a big fat arse "cartridge" that cant be substituted for .22's. Perhaps if you add extractors and have it chamber the whole round, or a sheath around the .22 it could work, but this complicated and this small you would have better luck making the original.

[ST]

For some reason no patent pictures work for me. Same goes with a number of different places, must be something up with my internet settings or something, crazy.

[nbk2000]

I knew that if someone looked they'd find them. ;)

They use the cartridges to avoid the Destructive Device classification a gatling using modern cartridges would have, similar to a machine gun (which it is).

If one were to use cardboard tubing of the proper size as cartridges, cap gun percussion caps, Vit C propellant, and 3/8" steel shot, it should be fairly simple to replicate.

But adapting the mechanism wouldn't be THAT hard. I've even seen ads in various gun magazines for plans and parts to make a .22LR gatling replica.

You wouldn't want to bother with the full replica, since I'd imagine the idea is to make a portable version to carry around ala Jessie Ventura in Predator. Feed mechanism would have to be some kind of chain-link to ensure a constant supply of ammo.

Maybe if you were clever, you could come up with a pnuematic device that would blow the rounds down a flexible tube into the gun which would then load them in.

And you need a TIFF browser plug-in to view patents on the USPTO site. Look up "alternatiff" on the net for one.

[zaibatsu]

<a href="http://www.howstuffworks.com/machine-gun2.htm" target="_blank">http://www.howstuffworks.com/machine-gun2.htm</a> this might help a bit, but it may be a little simple for you

[ST]

Theres no such thing as too simple, the whole point is to do it as simple as possible, i spent all night looking through that site, thanks.

The problem i see is that there is a lot of parts that have to be made identical, i'd hate to try making all the springs and firing pins etc. for every barrel all exactly the same, you would end up with some working some not, its best to keep all the fiddly parts together in one action so it either works or doesnt at all so is far easier to fix. Also that many moving parts on something this fast is bound to be troublesome, may work with a gatling gun but a minigun?

The whole point to using .22's is to have it inexpensive and easy to run, imagine trying to make a few thousand cartridges only to last a minute or two.

From what I gather from the pics, the "cartridge" in the gatling gun isnt even chambered when its fired, its just pushed up against the barrel, so a heavy sheath around the .22 could be used, but again ... a few thousand custom .22 sheaths doesnt sound cheap.

So, personally i dont think it can be done without chambering the whole round, heres what i come up with, it assumes that the case can be ejected via the pressure in the barrel on firing.

<center>
http://st.9f.com/action.gif
Are these pictures still working? If not, picture above is bottom pic in signature.
</center>

As the round fires, the firing pin is forced back and case ejected. At the same time another is pushed into the next barrel by the other end of the "arm". You probably wouldnt be able to get the cartridge fully chambered fast enough, so a ramp could be used to gradually feed the round in the rest of the way as the barrels spin.

[ January 12, 2002: Message edited by: ST ]

[ January 12, 2002: Message edited by: ST ]</p>

[skumjustice]

This is how a minigun/vulcan works internally. This is a freakin awesome 3dcad video. Finally it all makes sense!!!
ftp://coz-fx.com/download/CozGau17.avi

[angelo]

very nice video, it shows just how complex it is.

It seems if you have speed control included than you won't have to fire at full rpm, thus not wasting 4000 rounds in one minute.

[DimmuJesus]

There are some people that make gats out of AK-47s and Ruger 10/22s. This idea may help in some way, I believe I saw a couple, or at least ads for people who will make them for a cost if you supply the guns at www.gunsamerica.com

[Jacks Complete]

Sorry, I have to ask this...

Why have a big heavy multi-barrelled minigun/gatling gun, if you aren't going to fire at 4000rpm?

The main problem with all these designs is the ammo feeder. Has anyone thought of a good way to feed the beast without spending hours putting bullets into clips, belts, feeder cartridges, etc.?

Also, you will want some kind of brass-catcher or collection shoot.

The gatling gun design is actually very simple. Try to visualise just one barrel the whole way through the firing cycle. Forget all the other barrels, as they are exact duplicates, just at a different point in the cycle.

From empty, it picks up a loaded cartridge, then the bolt gets closed by a rod pushing it forward. The firing spring is cocked as this happens, the opposite of most rifles. Once the breech is closed, the spring is released, firing the cartridge. Next, the bolt is opened and the case ejected. Then it picks up the next cartridge...

The firing speed is completely user-selectable, within the range of the torque provision of the drive system at the lower end, and failing to feed or melting the barrels at the upper end.

[charger]

someone has already made a 22 minigun, you can see it here http://www.montysminiguns.com/brian.htm

[Jacks Complete]

montysminiguns.com rocks big time! Check out the minigun video under August! http://www.montysminiguns.com/miniofthemonth.htm

[maarten221]

Should make light work of jackrabbits! As for the loading chute - since it is .22, a relatively forgiving round when it comes to loading, you may want to look at a spring loaded system, much the same as on the FN P90, but without the rotation stage. This will allow the use of large magazines or chutes with minimal effort in loading since the only requirement will be that the rounds all face the appropriate direction.

[foxrdkll]

I like the posts you guys. I'm new and I appreciate the fact that you all know what you're talking about and you do your research!

The CAD video was awesome! It shows a fine piece of machinery. I've got a question though. Why not have a design much like what is in Bill Holmes book on the .22 machine pistol (i.e. loading mechanism w/ magazine) only with rotating barrels? It would still offer a little barrel cooling time. One person mentioned the rate of fire; is this one of your desires for the design?

"Why have a big heavy multi-barrelled minigun/gatling gun, if you aren't going to fire at 4000rpm? The main problem with all these designs is the ammo feeder."

So, I guess what I'm getting at is what are the objectives/desires in this design? ROF, barrel cooling, loading mechanism, weight, etc.?

[FragmentedSanity]

"Why have a big heavy multi-barrelled minigun/gatling gun, if you aren't going to fire at 4000rpm?"

I think the Ideal application for a multi barreled .22 would be as a sentry gun, controlled via remote - or by movement sensors when activateds. Would be quite a good defensive weapon. A couple of servos to aim the thing - or travel in pre-defined patterns. As such it wouldnt have to fire ultra fast - obviously it would be preferable to control the firing rate remotely as well - but even 20 rounds per minute would deter most assailants. Of course being able to up the rate to 500 rpm on demand would be helpful and not hard to incorporate in the design. 5000 rounds in a gravity fed magazine system would buy you considerable time to make good your escape while they believe your shooting at them - I spose with enough guns you could remotely defend an entire compound. Incorporating a self destruct - in the form of a big claymore - when it ran out of ammo is another defensive measure. It would be nice if the self destruct could seal the entrance it was guarding as a final act of defiance.
The Main point is the a slower rate of fire would be quite efective -and even better in some situations : imagine 5000 rounds at 100 rpm giving you 50 minutes of constant firing. No one would want to enter its line of fire and if the did they would sustain multiple hits in very little time.
IMO thats a much better idea than having a gun that will cut down most anything in its path but only works for a minute or so.
Such a weapon would also be great mounted in a vehicle, as an offensive weapon; in which case the higher firing rate would be better. The idea being to drive in - lay out as much lead as quickly as you can then drive off.
What it comes down to is that a high firing rate is more likley suited to offence, slower to defence - so the weapon needs to be designed with a purpose in mind. Having variable speeds would be the best idea tho - making the guns more adaptable.
Another thing to think on is that if you make one of these you can obviously make more - so if you really feel the need to hurl copious amounts of lead around you just add more guns. 5 guns firing slower would put out just as much lead as one fast gun - but in a more random pattern assuming the guns were all set to shoot a different pattern - and without the problems of barrels overheating. 5 guns in 5 different locations is also a lot harder to neutralise than one single gun.
Many other ideas for sentry guns were discussed by NBK in the BB macine gun thread, I believe most of it could be applied to a .22 mini gun.
IMO even if you wanted a "Predator" style gun it would be best if you could alter the rate of fire - slow to provide covering fire and faster for attack. It just seems a waste to fire thosuands of rounds when after only a minute or so your empty and vulnerable, when you could still have a very rapid rate of fire but have a lot longer firing time.

[Blackhawk]

You woudln't be vaunerable, as a you are now carying a big minigun shaped club :P Serriously though, wouldn't 50mins of constant firing overheat the barrels? at 500rpm each barrel would still be firing an average of 1.4 rounds per second (assuming 6 barrels), thats not much but I would think it would add up. Of course a simple water jacket around the barrels would help a lot. But then there is still the matter of designing and building several miniguns, say 5 to defend an area, and then loading 25000 rounds into them (5000 each) for the coming gunfight. Oh and you would have to buy 25000 .22 rounds at once and try not looking suspicious too.

[PHAID]

The purpose of the minigun concept is that it keeps the barrels cool because they each have a short time that they are emty and exposed to the air.

The other good thing is that they dont jam, if you have a missfire it just keeps going and drops the unfired round.

[xyz]

Blackhawk, you could buy the ammo straight from the manufacture. I am sure it would be very common for them to receive orders that size from gunshops, clubs, etc.

And in FragmentedSanity's example, to keep firing for 50 minutes, they would only be going at 100RPM, not 500.

[foxrdkll]

What about a design that incorporates multiple barrels but with a single bolt? This could simplify design, construction and reduce weight. You could also include a separate or secondary ejector to allow for increased speed or a safety check. Then again, I don't know if this would produce too much of a problem with the bolt overheating if fired at an extremely high rate of fire.

[irish]

As far as buying 25,000 round's of .22 ammo goes those 5000 round "case's" that most gunshops sell come in a pallet of 50,000 rounds, I'm sure if you told them you where buying for a group of mates they would sell you a pallet with no questions asked (apart from maybe how you are going to pay for it :D ).

[CommonScientist]

ST -
"its run via a starter motor"
Im pretty good with automotive parts, so im pretty sure that the starter motor wouldnt work. Reason being that they burn up often on cars. It has limitations, you should only have it on for 30 seconds or less. Just trying to help.

[Blackhawk]

Starter motors in cars, especially with 6+ cylinders are under a lot of strain with very little cooling, try turning the crankshaft of a car and you will know just how much In comparison to this while heavily geared I think a .22 minigun would not be too hard. That and you could have active cooling via a fan directly attatched to the main shaft blowing air over the motor.

[xyz]

Commonscientist, your sig violates the rules. Please change it to something 3 lines long or less.

[ST]

Since when is a minigun going to be fired for more then 30 seconds continuously, and even then it aint the starter motor that will melt first.

[Blackhawk]

Well it is firing at a very low rate, and as a constant cover fire so you can get away, it is not like you are holding it, as stated above it would be part of some kind of autonomous tripod.

[Dave the Rave]

I like the idea of only one bolt and one firing pin, where the mechanics of feed and unload can be made by guiding rods.

The motor rotates a endless screw, which engages on the rod of the bolt, pushing it back and forwards, thus opening the chamber, feeding the cartridge, closing the bolt and firing the gun.

Then when the chamber is open, a bullet is taken of the clip and put on the port. As the bolt moves forwards, it pushes the bullet to the chamber, closing it. With the chamber closed, the firing pin is free to disengage the rod, firing the weapon. Then the screw engages again the bolt, taking it backwards, opening the chamber and extracting the bullet to the port, then the gravity do it´s trick


Or, the idea of guiding rods can be used on multiple bolts and firing pins:

After the shoot is fired, lets say, on the 3rd or 4rd barrel, the bolt engages the rod on the chassis of the gun. As the barrels rotate by the motor, the bolt follows it´s guide and moves backwards, opening the chamber and ejecting the spent shell. Whit the chamber open, it strips one new cartridge off the belt or clip and disengages the guide, thrus closing tbe bolt. as soon as the now feed barrel reaches the line of fire, another rod disengages the firing pin, firing the weapon. All these steps can be acomplished by the rotation of the axix by the eletric motor, without any need of gas operated systems.

[Tube]

here's a cool site you guys might want to check out if you haven't allready.

http://world.guns.ru/machine/minigun-e.htm

This is more of a history of the gatling gun development, as opposed to a 'how to make your own' reference. But, i saw a few references to the portable "Predator gun" in this thread, and the author of my link gives a good spin on how unrealistic the actual idea of a portable hand held minigun really is. (I understand that the predator gun was at least a .223 and this thread's about making a .22 so their would be a world of difference between the two. But, nonetheless the link's still a good read)

Aside from this little minigun section, it's a great gun reference site in general. so, if you're bored it might interest you to browse the rest of the site.

*this is my 1st post, so hopefully i'm not breaking any rules or getting too off topic here....

[pest3125]

Might be too much to ask for, but some sort of 'hopper feed' would be good - so you can dump in more ammo into a bin without worrying about filling magazines or belts ...

[CommonScientist]

Well its not that it "melts", it just burns out fires and such in it. And it has enough tourque in it to power a 40mm minigun with 6 barrels. So it might be overkill. You could use a motor from a vacume cleaner, but you would need to convert your power supply to a 120 volt system for maximum efficiency.

I thought the predator minigun was a 7.62 : .308. and the terminator minigun was the same one with a different grip/handle style.

[maarten221]

I saw an ad for a .22 Gatling gun in Shotgun news last night - if you could desigh something similar and instead of a hand crack, add a motor (low RPM) to it, it should be able to reach the 2000+ RPM ranges - taking into consideration the metals used in construction and the appropriate gearing. Looks like a Hella lotta fun though! Keep the hand crank and attach when showing the weapon off or when it is in storage, because that keeps it legal (sort of). The mag on the Gatling is a chute and the ATF doesn't seem to mind those with the higher capacities. I'll look up the website for the gatling when I get home and post it - very useful info and you can "purchase" blueprints - not that it sounds like y'all need them.

[maarten221]

HEre is the link: http://www.gatlingguns.net/

[Jacks Complete]

Using just one bolt and firing pin would be a bad idea! You then have a single point of failure! The iring pin breaks, and you are looking like the biggest loser!

Also, I think it likely that the heat build-up might cause problems as the bolt would get hotter, and hence expand faster and further than the barrels, which could cause a jam.

[tiac03]

A few questions

1. Does anyone here actually know what their talking about? Some have had some good points but most of the stuff written was rather useless. Now I don't pretend to know what I'm talking about when it comes to gun design, but some of the crap you are offering is just that.

Today lets just talk about the firing pins.

A) They call it .22 rimfire for a reason the "primer" runs along the rim and this is the reason that the firing pins on .22's arn't centred. This being said all your drawings have centred "pins".

B) a single firing pin any way you think of it is a stupid idea. Think of it this way a firing pin is made to hit a stationary object. This said all the strength of the firepin is due to the fact that the shock goes through its length (example of this is a nail). Now as soon as this single firing pin hits an object, that, rather than be sitting still (relative to the pin) has a side ways motion, it experiences a sideways push (take a dowel and touch it to the outer edge of a drum sander and you will see what I mean). This will have you going through more pins than rounds.
Anther problem with the stationary pin is that it has to be really timed well. These things combined also ruin your "grenade striker" looking firing pin idea. Rather than fire the round it will just rip apart your cartridge or get riped off itself. (also ultimately cutting a groove (sp?) into the "face" of your "advanced thread spooler")

To solve this whole problem just have pins that strike the round but rotate with the barrels. (look up the circular ramp design from the original gatlings probably the easiest)


2) Now for some of my ideas on how to make one of these beauties.

A) For ejection and intake once again following the original gatling is the way to go. (where the round sits is only half a barrel but once it gets to firing position there is a block that completes the barrel). This makes for easy intake and drop out ejection (as half barrel part becomes inverted shell falls out).

B) Whats the point of a big assed 6000rpm gun (the predator one only fired at 3000 because they had to hook up a 12 volt rather than a chopper 24 volt batt, and it didn't have enough juice and that was still quick). My advice is the smaller the better. (I assume since you are willing to spray that much ammo per min you arn't worried that much about accuracy). Use the shortest (practical) barrels possible, and keep the weight down. You are using .22 rimfire not 7.62 (.308). You don't need heavy or long barrels. (.22 is only good up to about 100-150 yards anyways)

C) If you keep the weight down you can then use something such as an electric or battery powered drill as what drives your gun. OR for those who have seen the gas powered drills in action can think about how amazing the thing would work, look, and sound.



Contrary to popular belief it isn't anywhere near easy to build a gatling gun. To make matters worse your plans revolve around a gas operated ejection (I think). Now unless you are an engineer who specializes in weapons systems I doubt you can accomplish that kind of ejection system. ( You first off need enough pressure to allow the gas to escape out the front of the weapon rather than ejecting the shell and having the "projectile" lodged in your barrel because all the gas went out the back (probalby F*cking you up in the process). If there is too much pressure on the back of the case the round will go out but the case will either stay in the barrel or eject half way and jam your little toy. (The whole point of a minigun is that it fires quickly without barrels heating up too much, and it doesn't jam)

Well I think I wrote too much already....

[JoeJablomy]

Aaarrgh.
1.You cannot, or at least would be a dumbass to, use one bolt for all the barrels. Not because it would overheat -the bolt, much unlike the barrel, is never in direct contact with 2000 deg gasses @ 20KSI or whatever pressure .22 gets up to. The case is, but it gets thrown off the bolt before it can transfer much heat. The reason you don't use one bolt for all the barrels is that then that bolt would have to move back and forth really fucking fast as each barrel comes into alignment. One bolt is used for each barrel because they are not actuated by some kind of 'rod' but by a really big elliptical cam around the outside of the receiver, and if it's a gatling gun then each bolt can only move back and forth relative to its own barrel. Does this make sense?
I haven't read the links, because they don't seem to work, but if you look at a good picture showing the inside of a gatling gun the above should become obvious.
See
http://www.globalsecurity.org/military/library/policy/navy/nrtc/14313_ch6.pdf

2. As for .22 LR ammunition and its handling by a magazine: What the . are you thinking, maarten221? The P90 fires a rimless centerfire cartridge, and yes, that one is pretty easy to handle, including feeding it through a P90 magazine. The problem is that .22 is not rimless. It is rimfire. It has to have a rim. And that rim catches all fucking manner of obstacles that cause stoppages, including the rims of other .22 cartridges like the ones after it in line, which do not want to be removed from the magazine at the same time as the one first in line. In short, the magazine/feeder will be the biggest problem, if you want it to have a decent capacity.

3. As for the rate of fire: If you want a 100 rpm .22, go to your local suburbanite friendly, consumerist bitchgunshop, and buy one of the exceedingly common semi-auto .22's. You can fire 100rpm from one of those by hand. You do not need a gatling gun to do that. Also, a drone gun that fires .22 at 100 rpm will not deter -anyone- except your mom. There are faceshields that can stop .22. Also, NO ONE tries too load a gun with enough ammo for 50 min. of continuous firing, unless they think they're going to be shot dead and not be able to reload the gun and don't realize that a .22 gatling gun could be taken out by piggy with the .50 cal sniper rifle once everyone finds out where it's located.

4. Heating: .22 doesn't heat up barrels very fast. What makes to biggest difference in barrel temperature on my .22 semi-auto is whether or not it's a really bright day and not really windy. Also, gatling guns are actively cooled by a very obvious mechanism: the barrels are whirling around in the air really fast. This induces the air to flow around the barrels, and cools them when their temperature exceeds that of the air.

To build a .22 nanogun firing @3000rpm, about the minimum acceptable capability for such a weapon, [and 20sec. is a long time for continuous fire] you could try to make it self powered by blowback as the original post seems to imply, but you absolutely need a bolt for each barrel to confine and support the case head and rim during firing. The reason is the same reason rimfire cartridges are always small and weak: the rim has to be really thin for it to work, and thus cannot hold 50 KSI internal pressure like a good rifle round. Rather, the rim and head must be well supported to hold up to the pressure the ammo Is loaded to, and a chambering "ramp" with a fixed firing pin will not provide this support. What would is a tiny little bolt with a fixed firing pin/protrusion that would dent the rim just as the round is fully chambered. Since this is a .22, this bolt would not even have to lock to the rotor stub. A good picture of a compact gatling bolt, for the GAU-8, is at
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2222826775&category=588
But please understand that most of the protrusions at the front are for locking and are, as stated, thus unnecessary for this design. In fact, with a properly designed cam, the bolt would begin blowback as the round goes off, just as in any other gun, and would drive the rotor by driving itself along the cam. Alternatively, the cam can be designed with a slight flat to keep the bolt closed during firing, with the drawback that it would necessitate an extractor.

To drive this gun, do not use a big, heavy ass car starter motor. Use a cordless drill. In this one package you have a pistol grip, trigger, battery, and geared, high torque motor. You even have variable speed. Just remove the chuck and thread a hole in the back of your main rotor for the shaft, and make the required mounting brackets.

Other notes:
Speed is necessary for the functioning of a fixed pin firing system. Elsewhere in the forum you will find it repeated that what sets explosives (like the lead styphnate priming compound in the ammo) off is both force and speed. I doubt you would have enough speed in a gun operating at 100 rpm to successfully fire .22 ammunition by anything but a spring loaded striker.
For feeding, which as stated is a much more complicated problem, I would use a single stack/column drum, pretty much a normal one. I would make it the size of a good submachine gun drum -after all, that's what this basically is- and with .22 ammo that size could contain at least a few hundred rounds. I would really avoid the helical drum despite its much larger capacity for reasons you should find obvious (see the second half of that pdf on vulcan installation). Reasons like you could never get the f**king thing to work.
As for belt feeding, .22 would have to use a pull-out belt, which is less than ideal, although the GAU19 does it. The bolts would have to have extractors on their outer edges to pull the round out of the belt, which would be pulled in by teeth on the main rotor, as the previous rounds are fired and the bolts blow back. Then again, that would screw up ejection. I don't know how you'd do it. But the belt wouldn't be that hard to make; you'd just use a flexible plastic strip for the base and maybe heat seal another strip onto that as the loops.
I should warn you though: gatling guns hate belts. Miniguns especially, although newer, more advanced designs can obviously take them without jamming too bad. The problem is, we're not even to a basic design yet.
Unless you can get/make really light “minimum contour” barrels, I would use maybe 3-5, which could make a pretty compact gun, too. It might be possible to make .22 LR barrels out of some king of stainless tubing.

One other topic that would bear a lot of discussion is how to make a receiver with an elliptical cam track on the inside.

[ST]

A) They call it .22 rimfire for a reason the "primer" runs along the rim and this is the reason that the firing pins on .22's arn't centred. This being said all your drawings have centred "pins".


No matter which way you look at it its going to be centred from one point of view. Now, the most logical way of positioning it is as ive drawn it, with the "firing pin" being a horizontal ridge to hit the full face of the case, thereby giving it the best chance to get a positive hit. Not to mention the main idea of using a stationary pin wouldnt work at all if I didnt know they were rimfired :rolleyes: . Stop trying to look smart by correcting your own stupid assumptions.

B) a single firing pin any way you think of it is a stupid idea. Think of it this way a firing pin is made to hit a stationary object. This said all the strength of the firepin is due to the fact that the shock goes through its length (example of this is a nail). Now as soon as this single firing pin hits an object, that, rather than be sitting still (relative to the pin) has a side ways motion, it experiences a sideways push (take a dowel and touch it to the outer edge of a drum sander and you will see what I mean). This will have you going through more pins than rounds.
Another problem with the stationary pin is that it has to be really timed well. These things combined also ruin your "grenade striker" looking firing pin idea. Rather than fire the round it will just rip apart your cartridge or get riped off itself. (also ultimately cutting a groove (sp?) into the "face" of your "advanced thread spooler")

Now you've made another dumb assumption that the stationary firing pin is shaped the same as a conventional pin, obviously this pin can be easily made very strong as its not designed to be hit by a hammer, and it can be as wide as it needs to be. A bevelled wedge shape seems most logical.

Your timing problem, thats only relative to the top left idea in first post, is solved by your first question, as the rimfire case leaves significant room for variations in the position of primer strikes. and gived the gear ratio in the picture it wont be spinning THAT fast.

Everyone please remember that this was designed to be as easy as possible, with little moving parts, you seriosly think that constructing multible firing mechanisms is easier and more likely to work then a single pin .... I dont think so! This is improvised and not meant to replicate a military weapon!

I still havnt seen any reason at all why a single stationary pin and a "recoilless rifle" type ejection will not work, obviously accuracy and power will be poor, but seeing as the only possible use for this would be running around pretending to be ED-209 whats does it matter!

Getting the round chambered is a totally different thing and very hard ... this is its only fault that I cant get around. Unless you want to just blurt off 8 shots then reload, in which point ejection isnt a factor either. Now imagine a multiple barrelled automatic revolver which is best accomplished by the moving pin (top left image in first picture).

JoeJablomy, your points are also made from assumptions, Niether of us know what speeds will be needed for the stationary pin to operate and ive never talked about 3000rpm "nanoguns" only a electric rotary barreled automatic weapon to be used for personal amusement! Dont be taken into thinking the way its done in military guns is the only way to do it ... A "rimmed rimfire" case brings up its own problems but also possibilities.

[tiac03]

Now lets get one thing straight, it takes someone who, at the very least knows the basic function of firearms to build one let alone a mini-gun. If you want a rifle that has only one firing pin give it one barrel. the point of the "mini-gun" is to fire rounds faster than single barreled firearms can. If you want a really slow firing one it would make more sense to just convert a semi-auto rifle to full auto (less costly too).

Now if you are serious about the mini-gun I would advise you to do away with the single firing pin idea, it won't work. (unless you were attempting to make one that fired like the multiple grenade launchers, which is dumb for a .22)

now if you are going to take the effort to pull your head out of your ass, I have found a few links that can help you. (some may have been posted already)

http://www.modelgatlinggunplans.com/pix/breechOpen.jpg
http://www.denvermechanicaldesigns.com/GUN_PARTS.html
http://www.gatlingguns.net/3d.htm
http://www.howstuffworks.com/animation23.htm
http://members3.boardhost.com/gatchat/
http://www.gatlingguns.net/
http://www.rkba.org/guns/principles/operating-systems/gatling.html

notice the # of firing pins = number of barrels for each one.

why I try to help people who are too stubborn to listen to others is beyond me.

[JoeJablomy]

1. I didn't say I knew wnat speed would be necessary, only that it isn't slow. No, no part of that is an assumption. I've pulled several hundred dud .22 bullets for the powder, most recently by gripping a round in a pair of pliers and using another pair to wrench the bullet out. From messing with the empty caps, and judging by the number of .22 duds there are at my shooting range, I can say very certainly they aren't that easy to set off reliably. I could probably crush the base and rim of an unfired .22 casing without setting it off.
2. You may have never talked about a real gatling gun, but it's been mentioned, and the alternative seems to really suck. If you want some POS with less performance than .22 at a low rate of fire, don't waste my time talking about it. This is the improvised weapon forum, and your amusing toy seems pretty lame as a weapon unless you plan to add a bayonet ;)

No, it doesn't have to be a strictly conventional gatling gun, but it does have to work. Anyway, 'rotary cannon' is another word for gatling. You Will need something to hold the rounds in line with their barrels before they are shoved into them, this is done by the fingers on the rotor of a real gun. You will need such a rotor on your own gun to make the rounds follow the loading ramp, unless you can come up with some other way of doing it, and if you're going to make a real rotor you may as well mill bolt tracks in it and use bolts for the reasons I've enumerated above. You didn't think you were going to make a high performance gun without machining something, did you? And before you come back about this not needing to be very good:
a)If no good, useless
b)if you don't need the performance of a multibarreled gun, use a single barreled one. You can just buy one, and won't have to fuck around with the 50+ parts you'd have to make with a dremel tool for the rotary.

Speaking of which, if you only want something with barrels that turn, you could make a barrel rotor and cam/lock system to align it with a stub barrel on a semi-auto .22. Use backward movement of the bolt to actuate the barrels, get a 50-rd magazine, and learn to shoot really fast. Your friends will never know the difference :))

[ST]

I will say again, this was only designed to be THE EASIEST way of getting automatic fire off, the multiple barrelled design was only chosen as it is the EASIEST way to do it. If we disregard magazines and chambering new cartridges, I challenge anyone to come up with an easier way to get 8-20 rounds off in automatic fire. As soon as everyone gets the "cutting down trees with blazing beams of lead" idea out of their minds we can get back to it being IMPROVISED.

You may of noted that this original topic was posted over two years ago, so I have no intention of actually doing it. The feeding problems were mind boggling, and i'll say improvising it is near impossible, this was a major problem with the blowback ejection, if it fails to fire a major fuckup jam would be guaranteed as a new cartridge trys to force its way in. I'll admit that the way its drawn will never work as a magazine fed automatic weapon. You would have to rely in the amount of barrels you could fit into it, which for a .22 would be about 20.

You can talk of "toys" and not a real weapon ... but then who here would actually use an automatic weapon for anything but amusement, same goes for the rest of the things discussed in this forum.

How can you call your ideas "improvised" if it takes a gunsmith to accomplish it! I choose to only talk about ideas that will be within the capabilities of most people, if that means *its* capabilities suffer - so be it! Also, improvised doesnt mean going out and buying a semi-auto rifle, even if it accomplished the same thing ... cant you see the difference!

With this said, Tiac03 & JoeJablomy you can continue your discussion on weapons that are out of reach for 99.95% of people, but stop directing insults towards me as we are talking about two very different things.

[Rhadon]

Let's not start a smack talk, I don't want to threaten to ban someone.

[tiac03]

I wasn't posting with the intent to be insulting I was posting to inform you that you're idea of "improvising" is what "Macgyver" is known for. You think you can strap a couple of things together spin them and you have an "automatic rifle". That is dangerous thinking. The amount of work you are willing to put on the project is only enough to make a single barreled single shot POC (piece of crap).

The ideas I put forward apply to anyone who is willing to put some effort, patience, and possibly a few bucks into making their own as Joe said "rotary cannon". (As simple as it can be made, and yet still be functional.)
Now if you want to build one with a pocket knife, a soup can and a lemon as a power supply, I advise you to go to the MacGyver fan site.

So anyone who is serious about it follow the few links I added before, and use your imagination (logically).

[JoeJablomy]

Tiac: I finally did look at your links, and the 3d images page was pretty good. It's nice to see the carrier block (I was calling it the rotor) fleshed out.
I've been thinking about it, and you're right about 'blowback ejection,*' it wouldn't be reliable at all. One detail of the RG-G models is that the extractor is on the outer side of the bolt, I guess for the obvious reason. It seems strange to me that the bolts extend clear out the back of the carrier, which seems to have a lot of wasted volume. I guess that's OK if you want a $10K gun, but for a lighter, cheaper version I would of course use SMG style percussion as I said (the firing pins are bumps on the bolt faces). This would eliminate the need for most of the stuff behind the carrier, and if the bolts were only held to the carrier by their tracks, with no tunnels, the whole cam assembly could be moved forward, too.
The GAU-8 is said to be extremely compact, and from the size of the bolt I can't doubt it! The bolt is about a third of a cartridge length long. We probably can't achieve that without ending up with finicky little parts that won't work, but we can definitely do better than the 5-length bolts RG-G uses. Specifically, we probably can get away with 1.5" long bolts, which would be exactly 1.5 length. They could probably be made from 3/8" bar stock, and it would probably be most practical to screw the cam lugs on.
It seems most likely that the RG-G gun had the bolts going through tunnels in the carrier to hold them to it very firmly. The alternative is to have the bolts be partiallly submerged in their tracks. It might also make sense to use square or hex bar for the bolts, although that could make it harder to mill them. (I don't really know much about machining, either) I think if you used 3/8" square stock with one edge facing out and one toward the gun central axis, it would be plenty big enough to hold a .22 round and still have enough metal on either side to hold it securely in the track.
One other possibility is to have the main cam track be inside the carrier, instead of around it, as a stationary cylindrical thing with the track milled in it. It would be a lot simpler that milling it in the inside of the outer casing. This would mean you'd need more barrels to have a core space big enough for it, and the cam-core would have to be supported by the back plate, but it would definitely make the receiver a hell of a lot easier to make. I think this might be the approach used on the GAU-8; in the pictures you'll notice the cam follower is on the opposite side from the extractors.
---Just checked, and the outside casing seems like it might have the track in it, but the pictures are all low resolution or have the feed guides in the way. Interestingly, the rotor is driven at the front of the receiver instead of the rear. See the bottom of
http://www.military-page.de/waffen/mk/gau8/gau8_01.htm
---Anyway, it likely doesn't have the cam inside the carried because it would be much harder to incorporate a clearing cycle if it were. It might not matter if the extractors are on the inside edge and the follower is on the outside; the ejector is probably some thing that catches the casing in the middle and throws it out as the carrier rotates. There seems to be a groove to accomodate such a device on the RG-G carrier.
---In fact, my used 30x173 durable dummy has a ring of nicks about 3" from the base, and a fired shell has one. They look like they came off the squared corner of something about .07" wide.


*I should have called it blow-out ejection; blowback guns use extractors so it's a distinct variation.

[tiac03]

Yea they based their design off of the "classic" gatling guns, so that is why it is built that way.

Your design ideas seem good. and the Idea of using the firing pins as really a protrusion off of the total is also a good idea because it would allow for less small moving parts to have to worry about.

But you proved my point. The best kind of posts in these forums are the kind where people look something up and add their own thoughts on improving it. Almost like reverse engineering. By the end you take the best ideas from everyone involved and design one from that.

I just wish I remembered the name of the site that had the video of the inner workings of a black powder gatling gun in motion. If I ever find it I'll post it.

[Marcus]

I uploaded the video I think you are talking about to a geocities account here: http://www.geocities.com/marcuschurch2001

Unfortunatly as it is quite large one download appears to exceed the free allocated data transfer.

[tiac03]

From what I remember yea that seems to be the one. Thanks. You remember what site it was from?

[ST]

Im pretty sure that vid originally come from gattlinggun.net (now dead). It shows how feeding and extraction were not an issue with the original gat, as the cartridge was also the chamber, therefore was as simple as letting it fall in and out.

[JoeJablomy]

A few other thoughts:
The GAU8 does use a cam track in the receiver casing like any other gatling. You can see it in the picture at the bottom of the German page I linked to, right next to the feed mechanism by the orangish band on the main drive shaft.
Also, feeding won't be as much of a problem as I thought. A gatling gun should take cartridges by pushing them out the side of the feeder rather than pushing them straight forward. The rim can get in the way of a cartridge going forward, but shouldn't be a problem it it's pushed to the side. What we do have to do is come up with a magazine that retains cartridges while allowing them to be moved out the side. I can think of a few ways to do it, but don't have a way to post images. Anyway, does anyone know about gatling magazines and how they worked?