
Centrifugal Machine Guns - smacktoward
https://armourersbench.com/2019/12/08/centrifugal-machine-guns/
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tyingq
2000 rounds per minute is pretty impressive. Though miniguns/Gatling do much
better these days...6k/minute.

And not terribly complicated in how they work. The concept fits mostly in one
animation: [https://qph.fs.quoracdn.net/main-
qimg-e01cffa77db21231f6d9da...](https://qph.fs.quoracdn.net/main-
qimg-e01cffa77db21231f6d9da19970d9ef3)

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natmaka
In a similar vein the H&K G11 also had ambitious objectives and was shock-full
of clever ideas, however such beasts make the KISS principle (rather decisive
for a weapon) difficult to follow.

[https://www.youtube.com/watch?v=QGKcvM2Hh4g](https://www.youtube.com/watch?v=QGKcvM2Hh4g)

~~~
irjustin
Oh man, that video reminded me of Metal Storm[1], something I hadn't paid
attention to since 2008.

The idea seemed so cool to the college grad in me. Clearly there are problems
with ammunition handling in actual battle situations and/or long term storage
that probably made this a non-viable war machine similar to the G11.

[1]
[https://en.wikipedia.org/wiki/Metal_Storm](https://en.wikipedia.org/wiki/Metal_Storm)

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bradyd
The Mythbusters built one of these.

[https://www.youtube.com/watch?v=Y3cRNEyUTF8](https://www.youtube.com/watch?v=Y3cRNEyUTF8)

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irjustin
Love the idea from an absurdity aspect.

Accuracy is very low, portability requires a vehicle, wear is quite high on
the "outside" side of the channel.

Feels as effective as a repeating shotgun mounted on a car.

~~~
lightedman
"Feels as effective as a repeating shotgun mounted on a car. "

Dunno, an AA-12 loaded with HE-12 explosive rounds mounted on a car or truck
could be a very effective mid-range area of denial tool.

~~~
_djo_
See the PAW-20 for an example of this taken to its logical conclusion.

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dmos62
Good overview of PAW-20
[https://www.youtube.com/watch?v=QHbqHx3TLBE](https://www.youtube.com/watch?v=QHbqHx3TLBE)

~~~
bradknowles
Wow. That was a wild hour-long trip down into weird and wonderful weapons!

Thank you!

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wiggler00m
_It wasn’t until World War One that the concept began to be considered again.
In June 1918, Major Edward T. Moore and Saul Singer filed a patent for a
centrifugal machine gun powered by an electrical motor (US #1,332,992). The
motor spooled up the centrifugal barrel assembly to rotate extremely quickly
and impart centrifugal force on projectiles. According to Julian Hatcher the
gun could fire steel ball bearing projectiles at approximately 1,200 feet per
second. Fire was controlled by a stop pin in the ammunition feed tube. Moore
claimed the weapon could fire a projectile 1.5 miles with enough force to kill
a man. He also suggested the weapon’s rate of fire approached 2,000 rounds per
minute. It appears that Moore’s gun may have been tested in 1918 but Hatcher
described its accuracy as ‘extremely poor’._

~~~
6nf
Modern bullets are not spheres because spherical projectiles don't want to fly
straight, especially when you impart a bunch of spin on them first.

~~~
notduncansmith
It's true that the spin from a centrifugal gun is unlikely to make bullets fly
straight, although ironically "impart a bunch of spin on them" is also one of
the foremost techniques for making bullets fly straight:
[https://en.wikipedia.org/wiki/Rifling](https://en.wikipedia.org/wiki/Rifling)

> In firearms, rifling refers to the helical groovings that are machined into
> the internal (bore) surface of a gun's barrel, for the purpose of exerting
> torque and thus imparting a spin to a projectile around its longitudinal
> axis during shooting. This spin serves to gyroscopically stabilize the
> projectile by conservation of angular momentum, improving its aerodynamic
> stability and accuracy over smoothbore designs.

~~~
catalogia
Relating to spinning spherical projectiles, some airsoft guns impart backspin
on the spherical plastic pellets they fire to flatten their trajectory:
[https://en.wikipedia.org/wiki/Hop-
up_(airsoft)](https://en.wikipedia.org/wiki/Hop-up_\(airsoft\))

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chroma
I'm rather surprised that there isn't more innovation in firearms. For
example: Has anyone tried to build a rifle that fires inert pellets using a
combustion chamber powered by hydrocarbons (say… propane) and an oxidizer
(oxygen or nitrous oxide)? That would make ammunition much lighter and
cheaper, eliminate the need for brass feeding/extracting mechanisms, and allow
for "dial a velocity" by feeding different amounts of gas into the combustion
chamber.

Another possibility would be to have a belt that accelerates the projectile.
The "ammunition" in that case would be batteries and inert projectiles. Like a
propane gun, velocity could be customized for each shot by varying the belt
speed.

~~~
ajuc
I'm pretty sure the next big thing in small arms will be electronic triggers
in bullpups. Bullpups' main problem is weird trigger pull, electronic trigger
solves that, and also allows some more benefits (like automatic range-
adjustement if you put a cheap camera and rangefinder on the weapon).

Basically when you pull the trigger rangefinder finds the range and camera
takes photos one after another - waiting for the gun to get up enough so that
the point that was targetted will be hit with the range that was measured.

Gunner's hands are shaking a little so he will soon get on target, and then
the trigger is electronically released. You also need some timeout so that if
more than for example 100 ms passes without arriving at the target it fires
anyway.

The technology is there, very similar algorithms are used in smartphone
cameras to harness shaking hands for higher photo resolution. The main problem
is gun people distrust towards electronic in their guns.

~~~
remarkEon
The implementation would be fairly easy and an electronic trigger would be
neat, but imo the problem with bullpups will always be the somewhat awkward
reload technique that's required with that design. With an AR-15 style (or an
AK) I can reload it while keeping the weapon more-or-less on the target, and
dealing with malfunctions is easier because you have more space in your
"shelf". With a bullpup you have to reach basically into your armpit - it's
not comfortable compared to an M4.

(Again, my opinion.)

~~~
ajuc
With electronic trigger you don't need impact primers, you can just put a very
thin electric wire in each cartridge that gets hot when you pull the trigger
and ignites the powder.

So you can make magazines that aren't possible with the traditional cartridges
- like pipe magazines for strong rifle cartridges for example (hard to do with
impact primers).

I'm thinking a long plastic pipe with cartridges inside that is attached
paralel to the barrel. Then you just discard it with a button and put another
pipe magazine under the barrel from the front. Should be fairly comfortable
even with bullpups.

Additionally you can make a side port in the magazine so that you can load it
with single bullets like with old wild-west rifles :)

~~~
remarkEon
Interesting. Didn’t think of that. I’ve always liked the advantages of the
bullpup (longer barrel with shorter overall rifle relative to M4 designs).
Does this mean we’d be introducing some battery requirements for operating the
rifle though? That would be a flat no go for me then. Or are you saying that
pulling the trigger itself would generate enough charge to operate the
mechanism as you describe? Man ... turning all that stuff into plastic would
sure save on weight. But I’d be a little concerned about durability.

Someone really needs to try this. I’d love to mess around with a prototype.
What if you could 3D print your magazine pipes?

~~~
ajuc
Maybe it would be possible to use the trigger pull energy to ignite the
bullet, but it would probably make the trigger pull awful.

I'm thinking just a small battery, or even a capacitor. Charged by the recoil.

~~~
remarkEon
“Regenerative braking” meets “regenerative recoil”.

I love it.

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h2odragon
not high velocity, not high accuracy, but they can be effective. small
prototypes capable of delivering a _withering_ stream of BB's are well within
the capabilities of the misguided teenager.

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pontifier
Sounds awesome :) Are you speaking from personal experience?

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lightedman
We had centrifugal pellet guns at roadside carnivals 30+ years ago, glass
bottles were the targets. You could barely hit the target from 25 feet away
because the power simply wasn't there, and so many times those pellets simply
ricocheted right back at you. Those got replaced with the more 'fair' and
powerful tube/air-fed rifles which got used to shoot out a star on a piece of
paper (which in and of itself is a bit of a scam if you don't know the trick.)

~~~
obituary_latte
The trick being to shoot around the star I presume? That’s the only “trick”
I’ve ever heard of - curious if there is another.

~~~
tyingq
I believe it is a few things. Light finger to get single shots versus
repeated. First few shots to figure out how bad the sights are. Shoot around
the star until you have a good perimeter. Shoot the center to pop it out.

Though you can find credible marksmen that know all this, yet fail to win.
It's rigged.

~~~
LinuxBender
It is rigged, but it's the paper targets (star diagram). The paper
intentionally is strong enough that it is highly improbable that any bb/pellet
gun will have the force to knock out the remaining 20% of the outline of the
star no matter how accurate the shooter is. The inner part of the target will
begin to fold on purpose.

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leeoniya
is it feasible to make an electromagnetic machine gun powered by a battery or
bank of caps?

it would have the same advantages - cheap projectiles, no gunpowder and mostly
silent.

there's also this:

[https://m.youtube.com/watch?v=oWEqyrKLz6M](https://m.youtube.com/watch?v=oWEqyrKLz6M)

[https://m.youtube.com/watch?v=AEu9LLQpOF8](https://m.youtube.com/watch?v=AEu9LLQpOF8)

~~~
CoffeeDregs
Sure but it takes quite a bit of energy per shot. A fairly standard
7.62mmx51mm NATO shell puts out a bullet with about 4000 Joules of energy.
That's roughly a 0.4F, 100V capacitor or 2,000 200uF, 100V capacitors (around
$2,500) _per shot_. 20 rounds means that the gun has around $50k worth of
capacitors and that's before we start talking about rapid-discharge/charge
rate systems and energy transport.

Once the electrical rail machine gun is built, the per-shot costs are pretty
low (copper, lead, machining) and grid supplied energy (hello supply-lines),
but then a 7.62x51mm NATO round is $0.42 (in volume).

The rail guns that being trialed are monsters: not a whole lot of point in
shooting a $0.42 NATO round when you have nuclear power generator to recharge
the gun. By the same token, there's probably not a whole lot of point spending
$100k per soldier to kit them with a barely portable weapon that is matched by
a $2,000 AR-15 firing $0.42 mass-produced ammunition with a mature supply line
and easy portability.

But, yeah, I'd like to see them, too...

~~~
mlyle
Conversely, a base Tesla Model 3 puts out about 200kW sustained for longer
than most machine guns fire a string; 5.56 NATO is about 1800J; a M16 fires at
13Hz; if your process is 100% efficient this is about a power demand of 24KW
or about 1/8th of what the Model 3 draws from its battery pack.

Incidentally, such a Tesla-machinegun would not be regulated as a firearm in
many/most jurisdictions.

> the per-shot costs are pretty low (copper, lead, machining)

Bullets are not machined (except for exotic uses where insane accuracy is
required-- 1000yd championships employing exotic chamberings and weapons,
etc).

~~~
adrianN
> Incidentally, such a Tesla-machinegun would not be regulated as a firearm in
> many/most jurisdictions.

I'm reasonably sure that anything that can fire projectiles with more than a
few Joules is a weapon in Germany.

~~~
pmyteh
And it would be regulated as a firearm in the UK ("a lethal barrelled weapon
of any description from which any shot, bullet or other missile can be
discharged"; section 57 (1) Firearms Act 1968). There is also a specific list
of prohibited weapons in the same act which are firearms even if non-lethal.

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stevenhuang
I wonder if such a weapon could be feasible given the affordance of modern
technology. Very steam spunk, if so.

Not to say I condone such matters, but curiosity wonders the same.

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nabla9
DREAD from 2004

[http://www.defensereview.com/world-exclusive-video-dread-
wea...](http://www.defensereview.com/world-exclusive-video-dread-weapon-
system-devastating-jam-proof-and-silent/)

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artsyca
Centrifugal force is a fictional force it's due to centripetal acceleration

[https://en.m.wikipedia.org/wiki/Fictitious_force](https://en.m.wikipedia.org/wiki/Fictitious_force)

~~~
shalmanese
relevant xkcd: [https://xkcd.com/123/](https://xkcd.com/123/)

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aitchnyu
I guess the lack of rotation of the bullet made it inaccurate?

