Q: What exactly is a chain gun.


March 25, 2003, 05:16 PM
I understand (from TV) that the Armored Personnel Carriers have the Bushmaster 25mm "chain gun". Do we mean belted ammo - if not, how is it configured????

Enquiring minds want to know.


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March 25, 2003, 05:33 PM
I was lucky enough to be at fort benning for public demonstrations of the bradley fighting vehicle in 1986.

The 25mm cannon fires one shot per second on a disintigrating steel link belt. I was able to grab enough empties and links
for a nice wall display.

Each shell casing is made of steel of a diameter of about 37mm necked down to 25mm and stands about 7 1/2 inches tall.

I watched it being fired at some old M113 APC's at 1200 meters
cutiing through them like melted butter.

They opened up with the coaxial and TOW missiles and finished them off.

The back of the Bradley opened up and 9 soliders poured out
armed with everything from M16/203 M60's M249 SAW

They then took their positions and took out the rest of the targets down range.

I was 16 at the time and being 25 yards away from all this action
was about the coolest thing I'd ever seen up to that point.

March 25, 2003, 05:35 PM
A chain gun uses an electric motor to feed the ammuntion and cycle the action instead of using bleed gas from previous shells as in a normal semiautomatic rifle. If there is a misfire, the motor just pulls the dud out and loads the next one, ejecting the dud with the empties as if it had fired (the motor cant tell the difference).


March 25, 2003, 05:39 PM
Like if Husqvarna made a Gatling Gun ;)

March 25, 2003, 05:47 PM
Saw some video of the inner workings of one once - it has a chain mounted on 4 sprockets in a rectangle. As the motor runs the chain around, any point on it will go forward/sideways/back/sideways etc. The moving action parts are connected to the chain somehow, and the back-and forth motion cycles the action.

And it's a single barrel - not a Gatling style.

March 25, 2003, 06:03 PM
Like if Husqvarna made a Gatling Gun

No, THAT would be the GE mini-gun, the M-61 Vulcan, or the Avanger 30mm cannon (aka God's chainsaws) depending on what housrsepower you;re a want'n :D

March 25, 2003, 06:38 PM
Thanks for the question, and answers.

My wife asked me what a chain gun was and I got all puffed up to give a wise and worldly answer, which turned out to be "Uh..."

March 25, 2003, 06:45 PM
LOL boing, that's my standard answer when I bring home another revolver and she says "Don't you already have one of those?..."

Incidentally, get a copy of the Dillion Machine Gun Magic video, they have a short piece on the Bushmaster chain gun on the Bradley, showing some of the inner workings of the “chain action”. Very cool stuff.


March 25, 2003, 07:15 PM
In the MG Magic movie, Mike Dillon says the chain gun's designer was a motorcycle rider and based the gun on a motorcycle chain's workings.

March 25, 2003, 07:27 PM
I was breifly (6 mo.) a bradley gunner. I hated it, but the vehicle does have some nice capabilites.

March 26, 2003, 03:52 PM

Mike Irwin
March 26, 2003, 04:32 PM
Sort of like a chain letter.

Only one hell of a lot more fun.


March 26, 2003, 05:38 PM
The basic idea is that it does away with the gun being recoil or gas operated. That eliminates a lot of plumbing tacked onto the barrel - reduced weight and increased dependability.

March 26, 2003, 05:44 PM
So is it driven by an electric motor like the GE Miniguns?

Answering my own question: well duh, it's not recoil or or gas operated, and it sure as heck isn't hamsters on a wheel.

I'd love to see an exploded diagram or cutaway of this thing.

March 28, 2003, 08:00 AM
i got no idea

i just wanted to say



March 28, 2003, 08:23 AM
Cool link Ironbarr. Man, how come the Rangers in Somalia didn't have these instead of Humvees and Duece and a halfs. :fire:

March 28, 2003, 09:42 AM
Today's paper had an article of war news that had a statement triggering this post. It seems the BGs in the pickups nipping at our heels have found weak spots in the Abrams (and maybe others) since they disabled two Abrams. In the course of trying to answer my own question, the link above was found - it giving all kinds of info. A friend, trying to help me, about deluged me with links that have detailed info re all kinds of weapon systems - including the Abrams.

I'm a bit suspicious now that there is a major honey-pot of military info on the Internet - (and much have military URLs) that maybe this info is working against us in these times.

We have to remember that (1) this IS the World Wide Web - virtually unlimited access to every word and photo published; and (2) that everything on the net is recorded - somewhere - for posterity.

I know this and try to remember it, yet I still find myself publishing things that might - one day - bite.

Don't know the answers, but it seems to me that the military, with their control functions at least, might shut down or modify their weapons systems info distribution to the W.W.W.

Well - I could use some input here, so what say ye?


March 28, 2003, 10:09 AM
No tank, even the Abrams, is invulnerable. You're not going to brew one up or anything with an RPG, but you don't have to be Fellini to figure out that a lucky shot into the tracks or the engine decking could net you a mobility kill, and on a fluid battlefield, a tank like the Abrams that gets immobilized is going to be destroyed by its crew or other tracks in the outfit, rather than letting the Iraqis get their fingerprints all over it. This is hardly classified data. (Even if it was, don't you think that some Abrams driver in the Egyptian army may have slipped some info to Iraqi operatives in return for some bootleg Britney Spears DVDs? ;) )

March 28, 2003, 10:25 AM
Food for thought - thanks.

March 28, 2003, 11:56 AM

I'm just laughing my self silly with the mental image of Saddam deep in a bunker somewhere, listening to Brittany Spears...

'...whoops I did it again'

Yeah, you sure did. :p

March 28, 2003, 10:30 PM
IIRC, I've heard that thingie hanging under the nose of the AH-64 Apache is also called a chain gun.... Yup. Just looked it up. It's a 30mm M230 chain gun. The chain gun in the FPS game "Doom" is not REALLY a chain gun at all. Not really.

March 29, 2003, 12:51 AM
The M242 25mm chain gun, and the M230 30mm chain gun, use a chain driven by an electric motor to cycle the action of the gun.

One of many really neat things about the electric chain drive is that it allows the crew to select any rate of fire from 1 SPM (shot per minute) all the way up to the maximum rate of fire (about 225 SPM on the Bradley) by use of a rheostat.

Also, the M242 has two seperate feeding ports, drawing from two seperate ammunition hoppers per gun. This feature allows for the gunner/TC to change ammunition with just a flick of a switch.

For instance, one hopper can be stocked with Armour-Piercing, and the other hopper can hold High Explosive Incendiary. thus allowing the vehicle to be engaging armoured targets, but immediately change over to the HEI should a soft target wander onto the battlefield.

And, yes, the 25mm round is a full one inch in diameter.


March 29, 2003, 01:34 AM
IIRC, I've heard that thingie hanging under the nose of the AH-64 Apache is also called a chain gun.... Yup. Just looked it up. It's a 30mm M230 chain gun. The chain gun in the FPS game "Doom" is not REALLY a chain gun at all. Not really.

Interesting thing I learned from my pops, who worked on the Apache before Hughes Helicopters was bought out, is that the Apache has had aiming problems with the chain gun, specifically, the impact of rounds strings vertically, due to the mount flexing. Something the Army has partially fixed, and has learned to live with.

As to the chain part, the chain runs in a rectangular loop, and is attached to the bolt. I saw it once, but can't picture it totally. It's been a while. I do recall thinking that it looks complicated, but works OK, from what I gather.

March 29, 2003, 02:10 AM
Ok.....so how do chainguns, miniguns, and gattling guns differ from each other....or are they all the same type of gun with different names? You say tomatoe, I say tomato!

March 29, 2003, 06:40 AM
Nope. A Gatling gun has multiple barrels, rotated and operated by hand.

A minigun has multiple barrels, but the barrels are rotated and operated by a motor.

A chain gun only has one barrel, and the bolt-assembly is driven by a motor.


March 29, 2003, 04:03 PM
Short, sweet, and to the point.

Good post!

March 29, 2003, 04:25 PM
Sounds good, lawdog, but would you happen to have pics of each to help illistrate your point? ;)

March 29, 2003, 05:17 PM
Ask, and ye shall receive:

Gatling gun. (http://sites.state.pa.us/PA_Exec/Military_Affairs/museum/gun.jpg)

Minigun. (http://www.gunnerynetwork.com/graphics/mg/tn_ge20minigun20replica20right20front20quartering20full20view_jpg.jpg)

Chain gun (http://www.fas.org/man/dod-101/sys/ship/weaps/25mmgun.jpg)


March 29, 2003, 06:13 PM
In case some of ya'll didn't catch it re: the Abrams vulnerability, the Iraqis are hitting them with an anti tank wire guided missile, which was a bit of a surprise for us.

They know their tanks suck, and they didn't waste their oil for food money buying any more of them. They bought khormets instead.

March 29, 2003, 07:08 PM
Ho Ha Ho Ha
Ho Ha Ho Ha

Well don't you know
That's the sound of the men
Workin' on the chain gu-uh-un
That's the sound of the men
Workin' on the chain ...........gun.


March 29, 2003, 08:28 PM
geekw/a45: yeah the interesting thing is it appears they may be mounting a heavy atgm launcher on a technical (aka a civilian flatbed or pickup truck with reinforced suspension). That's not only unusual, but an unusually profligate waste of resources, since when technicals go up against Cav or a combined arms combat team the technicals end up being one shot wonders. Also if you notice, at least with the first two Abrams stopped the crews got out okay (even though they had to pry the driver's hatch open on one of them). That means they're probably only penetrating into one of the rear ammo storage compartments.

March 30, 2003, 03:57 AM
Well, see, whatcha do is, load lengths of chain into your 32 pounders for a broadside that will take out rigging, sails, and swabbies in the open, Mr Christian. Arrrrrrrrrrrrrrrrrr

March 30, 2003, 07:06 AM
That's why tanks need infantry support and vice versa.

March 30, 2003, 07:39 AM
The 'chain' is driven by a pancake motor on the aft end of the receiver assembly. The chain itself is driven from a 90* gearbox underneath the receiver. The chain attaches directly to the bolt. Proper 'timing' is critical during reassembly, and one of the common malfunction drills involves resetting the timing properly to clear a FTF.

BCGST (Bradley Crew Gunnery Skills) test station for disassemble/asssemble the gun was always a bitch.

M1 'vulnerability': What poppycock. EVERY tank is vulnerable somewhere. The M1 is just one of the least vulnerable to KE and CE (HEAT) rounds. The reported 'kill' of an M1 by resulted in a large hole in the RHA (rolled homogenous armor) of the aft skirts (not fore- DU skirts), some deck damage, and a crew contiuing the mission. An RPG-18 or Kornet in the grill doors did 'disable' the M1s after they left the MBA using 'limp home mode' (a protected mode designed to allow crewmen some maneuverability in the event of an engine catastrophic hit.

But a hint for ya: A Kornet requires the same visibility as a TOW for a shoot/hit, and minimum arming distance. Shooting in last week's sandstorm didn't involve such distances.

Recent Cavaalry Troop CO, 9 M1A1 and 13 M3A2
ODS Tank Company CO
Presently semi-retired

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