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The causes of weapon jamming and other misc firearm related questions.

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posted on Dec, 9 2005 @ 08:55 PM
-Why do weapons jam? sometimes it's dirt fouling up the weapon's internals, sometimes a miss-loaded round (that doesn't enter the chamber properly), but how about weapon overheating? will that jam a weapon? and why? personally I have never fired a machinegun before that is most prone to overheating so I can only use video-game logic here, in games they stop-firing when over-heated, I was kinda wondering why.

-Headspace, I often hear this term, esspecially when buying surpless rifles like Mosin Nagants, it's something you need to make sure of is alright, otherwise there might be dangers IIRC, can someone explain what this is exactly?

-Gauge, most often used in shotguns, the smaller the number, the bigger the bore, I understand this term is also used in pipes and such, can anyone explain this? since I am used to the metric system.

-Airguns as military weapons, sure enough i'm not expecting to see wars being fought with airguns, but I was wondering if they were ever considdered as specialist weapons such as a type of silent sniper rifle or perhaps something used in combination with non-lethal weapons? it would be hard to see any real advantages in this but I was wondering.

posted on Dec, 9 2005 @ 10:09 PM
"Why do weapons jam?" == Grdzero

Classic question. Why do any moving parts eventually fail ? Friction plus wear. Dirt contributes to
both friction and wear. What you are calling a miss-loaded round, I assume to mean a "stove-piped" round.
Proper design of the chamber and bullet carry mechanism should take care of all but the worst of dirty weapons
and improper pressure in the loads. (Which causes the auto function of the chambering action to fail to function
as designed. Simply use proper pressure loads and keep the action clean.)

The overheat problem for automatic weapons deserves a separate response.

You will probably get multiple definitions for head-space. Rather than give you one, let me explain my understanding
that has kept my rounds safe through years and thousands of rounds of reloading. There are multiple cartridge types
thus different definitions. What it means to me is that in a properly loaded round, upon firing of that round, the bolt face
and the base of the cartridge should not show relative motion in a perfect firarm. Ergo, the case of the bullet should not
have to streach back until it is engaged by the bolt face when fired. This can have drastic implications in most rifle cartridges but
not so much so in non-magnum pistols. (They do not generate enough pressure to place the brass in a near liquid flow condition.)
In older firearms, such as my old .303 Enfield, time and wear have combined so that upon firing, the .303 case will streatch back
along the anealing line which can rupture the case and scatter bad stuff back to the shooter. That means the case no longer
fully contacts the bolt when closed, and moves back to it when fired, but the front part of the case expands to grab the barrel metal
and the anealing line (about half an inch from the rim on .303 cases) is where this grabbing action stops, and only that part of the case
moves back, which thins the case along that line enough to be very dangerous. I can talk more to a specific round and case and firearm
if that was the intent of your question. If you shoot a lot and/or reload, these concepts are absolute SAFETY requirements.

The shotgun gauge question is easy. Try this reference

Airguns, an entirely separate topic as well, but you can hunt with them. Here is a sample .50 caliber airgun that is a serious hunting arm

Note it is recommended to use a SCUBA tank to refill the air chamber and these weapons are NOT silent. They are however rather
distinctive sound makers.

posted on Dec, 10 2005 @ 12:48 AM

Originally posted by GrOuNd_ZeRo
but how about weapon overheating? will that jam a weapon? and why? personally I have never fired a machinegun before that is most prone to overheating so I can only use video-game logic here, in games they stop-firing when over-heated, I was kinda wondering why.

When a weapon fires it generates friction heat, fire too many continuos rounds and the barrel can literally melt and cause catastrophic failure. First it will start glowing red, then white.

Firing four hundred rounds, continuos, through a SAW will melt the barrel. The RPK for can only fire about eighty rounds a minute if it is to avoid melting. Machine guns of all calibers have been known to melt and even the heaviest barrel is not indestructible.

posted on Dec, 10 2005 @ 02:43 AM
From a military weapons perspective, there are numerous reasons for weapons having a stoppage. Note, these work for the majority of military rifles.

1- Magazine stoppage. This is where the magazine fails to push the round into the correct position for it to be fed into the chamber. This can be caused by the magazine not being seated correctly in the housing, damage to the magazine, or the spring being manipulated in such a way as to retard the feed. Note that magazine stoppages are the most common type, causing an estimated 80-90% of all stopages. Check mag is seated correctly. If the problem isn't fixed, replace mag and carry on.

2- Failed ejection. This is where the empty case is not ejected correctly by the bolt, and it gets caught up in the ejection port. This stops the bolt re-engaging the chamber, causing a stoppage. Fixed by a 'cock, hook and look' manouvere.

3- Bolt failure to re-engage. This is usually caused by excessive fouling in the bolt lugs or chamber. It is usually fixed by forward assisting the bolt. If it persists and changing the gas setting doesn't fix it, then a quick combat clean of the chamber is needed.

4- Gas stoppage. This is caused by excess carbon build up in the gas parts. This may initially cause slowing of rate of fire, followed by repeated stoppages that are rectified by forward-assisting every couple of rounds. This is fixed by adjusting the gas settings.

5- Seperated case. This is where the base of the case is stripped off the round. The only remedy is to have it drilled out. Quite uncommon, but used to happen alot on SMGs using old ammo. Immediate action is to draw pistol or fix bayonets!

6- Dirt fouling. As the name suggests, the working parts are jammed up by dirt in the mechanism. This requires a combat clean.

7- Slow primer. This is where the primer of the round does not explode straight away. Usually caused by a faulty round. Very rare in decent quality ammo. Requires the firer to wait for the round to fire. Real life dictates that by the time you have forward assisted, the round will have gone off anyway.

There are other types of stoppage for different weapons, but these are the most common. Hope this helps.

posted on Dec, 10 2005 @ 04:45 AM
In AK-family weapons (my experience is from Sako Rk-95) the number one reason for failure is Magazine and more accurately magazine spring loosening after intensive use. number 2 reason is failed cartridge, ie. primer malfunction which has nothing to do with weapon itself. Only other "Jam" i've seen was a broken firing pin (one sinlge occasion, probably a manufacturing mistake) but never have i seen an AK get jammed because it was dirty.

As for pistols main reason is Firing with loose wrists, so that the slide can't fully retract, causing the gun to jam. In some Pistols (FN-HPDA for example) magazine "lips" get too separated in use causing a mis-feed, this can be fixed by squeesing them back in with suitable tool in hand.

Belt-fed weapons seem to jam most often due to badly loaded belt...

As for overheating most LMGs can take about 100 rounds before barrel starts go bad, usually military orders troops to fire much shorter bursts in order to increase weapons lifespan (side note PKM can easilly fire 100 rounds with no damage to barrel, but recoil springs start to loosen fast after that)

posted on Dec, 10 2005 @ 11:09 AM
Thank you for the responses, most of these I already had knowledge of but I wasn't completely sure, esspecially the headspace issue which I later looked up on Wikipedia, they had a good definition of it.

Overheating was something I was not very knowledgable about so I asked, I wasn't sure if they actually jam or not.

posted on Dec, 11 2005 @ 02:35 PM
One addition to overheating some closed bolt rifles or SMGs might cook, causing a round to go off without trigger pull, due to chamber being too hot when the round loads in...

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