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Historical Frequency of Jams


Kozure
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Not a rant, a complaint or a bug report; just a question out of curiousity:

Historically speaking, how often did crew-served machine guns jam?

Obviously this varies with the quality of the weapon, the training of the crew and the harshness of the climate that the weapon is being used in... but as a rule of thumb, how often did machine gun designers expect a stoppage due to jam, misfire or misfeed?

I ask because I don't think I've ever fought a battle in CMBO, CMBB or CMAK where one of the weapons didn't jam. It seems that if I have two to three weapons, at least one of them will spend at least one or two minutes being jammed. Given that MMG/HMG support can be critical at points, this can put a real dint in a tactical plan.

Once again - not saying this is a bug or that it needs to be fixed - just hoping to hear opinions on the subject.

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I don't know about historical frequency, but I did a little time in the infantry as an M-60 gunner (national guard) and those things do jam from time to time. More so, perhaps, you get overly hot barrels and have to change out the barrel or let it cool down so it doesn't warp. Those are probably reflected in CM jams too. I would guess that the program has the chance of a jam ocurring increasing the more you fire the weapon....

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I suppose a jam can be rationalized to represent any minor weapons malfunction - broken firing pin, warped barrel, bent extractor, fouled ammunition belt, etc. In game terms, they would have the same effects - ie a temporary stoppage.

Gun crews were trained to replace firing pins, for example, and spares were carried in the parts wallet/pouch by the assistant gunner.

I realize this doesn't answer the question, but perhaps it does explain why "jams" are so common?

Lots of little things to go wrong; I remember being on the rifle range once and resting a magazine on the ground. A bit of snow got into the lips of mag and unthinkingly I put it into the weapon and fired. What could possibly go wrong,eh? Well, the snow instantly turned into ice and the weapon stopped completely; had to walk off the range and take a bore brush to the chamber to clear out all the ice. Not unreasonable to think a belt of ammo dropped in the snow and hurriedly fed into an MG might have the same effect - ie the crew having to stop and frantically brush the ice out of the chamber.

I suppose that the presence of spare firing pins, etc. being issued with each gun kind of tells you that indeed, the designers realized this would be a problem in action.

IIRC, a good Bren team could replace the firing pin in less than a minute.

I wonder if jam times are linked to crew experience in-game? If not, they should be. Experienced crews would prevent jams (or shall we say "weapons malfunctions") from happening in the first place, and once they occurred would be better suited to fixing them quickly. In the Commonwealth, infantry soldiers were trained in IAs - Immediate Actions. For example, a broken firing pin could be instantly diagnosed by examining the primer on a cartridge that didn't fire; if the primer was not struck, you changed the firing pin. Inexperienced crews would not know to do that, and so their jams might take longer to fix, as the section commander comes over and has to diagnose for them, etc.

[ January 08, 2004, 03:49 PM: Message edited by: Michael Dorosh ]

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Originally posted by Michael Dorosh:

I suppose a jam can be rationalized to represent any minor weapons malfunction - broken firing pin, warped barrel, bent extractor, fouled ammunition belt, etc. In game terms, they would have the same effects - ie a temporary stoppage.

Gun crews were trained to replace firing pins, for example, and spares were carried in the parts wallet/pouch by the assistant gunner.

I realize this doesn't answer the question, but perhaps it does explain why "jams" are so common?

Lots of little things to go wrong; I remember being on the rifle range once and resting a magazine on the ground. A bit of snow got into the lips of mag and unthinkingly I put it into the weapon and fired. What could possibly go wrong,eh? Well, the snow instantly turned into ice and the weapon stopped completely; had to walk off the range and take a bore brush to the chamber to clear out all the ice. Not unreasonable to think a belt of ammo dropped in the snow and hurriedly fed into an MG might have the same effect - ie the crew having to stop and frantically brush the ice out of the chamber.

I suppose that the presence of spare firing pins, etc. being issued with each gun kind of tells you that indeed, the designers realized this would be a problem in action.

IIRC, a good Bren team could replace the firing pin in less than a minute.

I wonder if jam times are linked to crew experience in-game? If not, they should be. Experienced crews would prevent jams (or shall we say "weapons malfunctions") from happening in the first place, and once they occurred would be better suited to fixing them quickly. In the Commonwealth, infantry soldiers were trained in IAs - Immediate Actions. For example, a broken firing pin could be instantly diagnosed by examining the primer on a cartridge that didn't fire; if the primer was not struck, you changed the firing pin. Inexperienced crews would not know to do that, and so their jams might take longer to fix, as the section commander comes over and has to diagnose for them, etc.

Yeah, a green crew should jam a lot more often than an experienced one. There is a lot that goes into weapons maintenance, as Micheal points out. Especially in harsh environments. Try rubbing sand into the belt before it gets fed. In my relatively limited gaming time with this system, I have found the frequency of jams to be realistic. Still very annoying, nonetheless.
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Hi all

One thing I noticed when watch coverage of combat in Iraq was how often the vehicle mounted 50 cals needed to be recharged.

Basically the gunner would fire a burst or two, recharge, fire again, recharge, etc.

Either there was a large number of dud 50 cal rounds in Iraq, or continuous usage forced the gunner to occassionally recharge the MG due to residue buildup in the chamber.

A jam can indicate everything from a dud round, a case seperation, barrel overheat, kinked or broken links, or simply a biuld up of junk from continuous firing.

The more you fire a weapon without cleaning it the more likely it is to jam, so jamming should occur more frequently as a MG expends its ammunition. And some jams should be unrepairable on the battlefield.

Regards

A.E.B

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I spent a little time firing with the FN MAG(basicly I qualified with it as well as carried&fired it on some exercises).

Now the FN MAG is as far as I know based on the MG42 and known to be very reliable. But damned if it didn't screw up alot anyway.

Never any machinefailings(the gun never broke on me) but there were ALOT of other stuff.

First off. Every 250 rounds of fire you had to change the barrel(faster if on continuous). On the FN Mag that was easy and only took a few seconds though. The MG34-42 doesn't look as easy to switch though.

Then there was the problem of faulty ammunition.

Now the 7.62 Swedish NATO is reliable ammunition. But as a machinegunner you go through ALOT of rounds and every now and then there will be a case where it's a dud or it had some imperfection that prevented it from being ejected properly.

So there you have a few more stoppages. In the case of not being ejected properly a very timeconsuming stop.

And WWII ammo was not as good as the stuff we have today.

Built up residue. Now the FN Mag was very forgiving when it came to residue. But after some thousands of rounds it was an issue. And concerning the ammunition standards of that age there would have been more residue than today.

Dirt into the mechanism. It happens....alot. Even when you're very careful it's in the nature of a gun to get dirty when you're running around in the terrain.

Temperatures. At least the FN Mag was very annyoing when it came to temperatures. At least compared to a modern assultrifle.

It was a tricky thing setting the correct gas pressure. If it was too high you increased the risk of deforming the cartridge so that you got a jam due to ammunition problems.

If it was too low the gun would just stall because it didn't have enough power to complete it's cycle.

And the gas power necessary depended on outside temperature, residue buildup, how hot the barrel became etc.

Then there were faulty links as well as other odd errors.

So I imagine that the jamfrequency is quite accurate.

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The actual frequency of something going wrong with a weapon is quite low. On the other hand, the frequency of a stoppage for whatever reason is much higher. Simple things like having to dig ammo out of a pack (very common on the attack) or a twisted belt can stop firing for a short period without being a malfunction.

On the whole, I have found, both in RL and CM, that an individual weapon might "jam" once every 3 or 4 engagements in the same series (without any down time for serious cleaning) but out of a section a stoppage will occur in one of the guns in about half the actions.

One thing about the .50 being recharged frequently. A major cause is poor fire discipline. If you fire short bursts, 2 or 3 rounds, which soldiers often do because the weapon walks off the target, the weapon tends to jam. Keeping up good 6 to 9 round bursts will allow you to fire all day. The gas mechanism just doesn't get into its groove, so to speak, with short bursts. Experienced gunners know how to brace the weapon properly and maintain a good rate of fire.

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A most interesting thread, but I simply can't resist.

"The frequency of jams is less than that of jelly, but greater than that of preserves, which themselves are far more common than marmalades, compotes, and most assuredly lemon curds."

HANDBOOK OF TOAST, SCONE AND MUFFIN TOPPINGS,

First Ed., Copyright 1990, Food Fetishists, Inc.,

New York, New York

Regards,

John Kettler

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I am looking through my book "Blood Red Snow" by Gunter K. Koschorrek (combat on the East Front) for his comments on ammo for his MG. I can't find it yet, but I recall him mention more than once his problems with jams from shellacked (steel?) cartridges. Apparently, there was a shortage of brass in the German arms industry, and they were using steel that was shellacked to replace brass (hope I remembered that correctly). Anyway, the experienced veteran would always save 2-3 belts of "good" brass cartridges for the critical moments with his MG(like when Ivan was doing a human wave in his direction and only a 100m away).

So in his case, ammo and experience played a part in how he survived (or very nearly did not).

For what it's worth,

Ken

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Even though WWI Vickers/Maxims were stationary and watercooled machineguns which didn't even bother to attempt to make the weapon mobile(thus there were no compensations to reduce weight) I highly doubt that they in the field fired 10000 bullets without a hitch.

Being watercooled eliminates one problem. Being stationary eliminates the problem of mud and similar problems related to movement. Being designed to be stationary meant that things like the internal mechanism could be made alot more reliable.

But when considering the poor ammoquality of WWI as when compared to today(as frequently brought up by WWI flyers memoirs) I am quite sure that firing those 10000 rounds flawlessly were more of an exception than fact. Add to that the problem of cloth belts(which I believe was popular in those early machineguns) those 10000 rounds weren't fired during rain either.

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The MG34-42 doesn't look as easy to switch though
The MG 42's quick release barrel could be changed by an experience gunner in five or six seconds.
from HERE

The original MG34 proved the soundness of the design, but it was susceptible to stoppages caused by sand and dust and was generally demanding to maintain. Moreover, as a pre-war design it was complicated to produce. The MG42 was commissioned to eliminate these faults, in which it succeeded. There was no question of it replacing its predecessor though and the two types both remained in service side by side.
from Here

The Bren was a gas operated weapon which held the bolt group to the rear between firing. It came with a second barrel which could be quickly changed and a host of spares. It soon became the basis of the Rifle Section, the first line of defence against air attack and also the armament of the Universal Carrier and several models of Scout Car. It proved itself utterly reliable in all climes and conditions, the only modifications being to simplify production with the Mark 2 and to shorten the barrel in the Mark 3.
Bren gun info from same site.

[ January 09, 2004, 11:34 AM: Message edited by: Dinsdale ]

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Originally posted by John Kettler:

A most interesting thread, but I simply can't resist.

"The frequency of jams is less than that of jelly, but greater than that of preserves, which themselves are far more common than marmalades, compotes, and most assuredly lemon curds."

HANDBOOK OF TOAST, SCONE AND MUFFIN TOPPINGS,

First Ed., Copyright 1990, Food Fetishists, Inc.,

New York, New York

Regards,

John Kettler

That's impossible! The historical superiority of the German K42 Ausf A Apfelkriegkonfitüre over the relatively more robust but tasteless British Preserve, Plum Mk I, the Marmelade, Orange Mk III or the overly sugarly lend-lease American M1 Strawberry Jam has been proven in dozens of tests at the Breakfeast Testing Grounds at Aberdeen. This despite the appearance of the much-improved M1E2 Grape Jelly, which is considered by some to be the definitive toast spread of the war, and its match, the K44 Ausf D Himbeermarmelade with Zimmermit paste jar coating.

;)

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Perhaps one of you clowns might post about something you know - ask the German speakers about schmalz and schmiere; the former is too disgusting to be made up. If I am remembering correctly, it was half marmalade, half bacon fat and was a German staple in the field. They even had a piece of kit devoted to carrying it; the famous "butter dish" you see re-enactors buying on ebay. The Bundeswehr and NVA both carried on the tradition and their butter dishes live on.

And the Canadian delicacy in World War One was "Plum and Apple Jam".

Now, the bonus question - Canadian soldiers, when they were lucky enough to get them, loved to eat "CPR Strawberries". They weren't strawberries though - Kozure (or anyone), do you know what they really were?

Hint - CPR of course stands for "Canadian Pacific Railway".

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Originally posted by Michael Dorosh:

Perhaps one of you clowns might post about something you know - ask the German speakers about schmalz and schmiere; the former is too disgusting to be made up. If I am remembering correctly, it was half marmalade, half bacon fat and was a German staple in the field. They even had a piece of kit devoted to carrying it; the famous "butter dish" you see re-enactors buying on ebay. The Bundeswehr and NVA both carried on the tradition and their butter dishes live on.

And the Canadian delicacy in World War One was "Plum and Apple Jam".

Now, the bonus question - Canadian soldiers, when they were lucky enough to get them, loved to eat "CPR Strawberries". They weren't strawberries though - Kozure (or anyone), do you know what they really were?

Hint - CPR of course stands for "Canadian Pacific Railway".

I had to look that one up, I'm afraid, though I had a vague recollection of the term from reading "Vimy" by Pierre Berton.

Since I googled it, I'm disqualified and thus won't provide the answer.

Schmaltz - the Yiddish version of the German word above, has entered the English lexicon as something overly sentimental or showy - "That song was waaaay too schmaltzy." Sounds very appropriate and conjures up images of something slathered in chicken fat.

Yiddish has such great words for sentiments that take too long to explain in English.

As for disgusting rations... reading some of the descriptions of typical Canadian rations aren't very appetizing either. The infamous "compo tea" with premixed powdered milk and sugar in it conjured up retch inducing moments whenever George Blackburn mentioned the "skin" it developed when it got cold in his book "Guns of Normandy"

Wow... this thread is so far off topic...

-AHEM-

OK - thanks for everyone's input on jams, misfeeds, misfires and other sources of stoppages in machine guns. I had figured that the catch-all indicator "jam" did indeed represent other stoppages due to a variety of reasons. Evidently other people are frustrated by that little three letter word as often as I.

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The reference to CPR Strawberries in "Vimy" had me baffled for about 15 years. Then at Christmas dinner, my dad says "pass the CPR strawberries." The answer had been at home all the time, if only I had thought to ask.

Kitty, if you sing anything like the FSSF fights (and I bet you do), then I have nothing to fear.

<font size=99>BRING IT ON</FONT>

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Originally posted by Michael Dorosh:

</font><blockquote>quote:</font><hr />Originally posted by Andreas:

</font><blockquote>quote:</font><hr />Originally posted by Michael Dorosh:

Kitty, if you sing anything like the FSSF fights (and I bet you do), then I have nothing to fear.

Nasty, brutish, and quick? </font>
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