# pistol caliber kaBoom!



## SJC (Sep 7, 2009)

I have heard about the potential dangers of an unsupported chamber in some pistols. Even with the understanding that this problem is rather rare and often an issue more with a specific round than the gun, it makes me wonder: is the unsupported chamber an issue with handguns only, or do the pistol caliber carbines have the same designs? Maybe the question is, is the unsupported chamber a characteristic of handguns, or handguns calibers?


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## Carol (Sep 8, 2009)

The term "unsupported chamber" is bit of a misnomer.  Its not limited to pistols, or to specific calibers.  Its a characteristic of the loading system of semiautomatic firearms (not just pistols).  When a round is loaded, it travels from the magazine, up a feed ramp, in to the barrel (the chamber) where it comes to a rest until the gun is fired.

Some barrel designs expose a bit more of the rounds casing than others.  The ones that expose more are referred to as "unsupported chambers"

Here are some pictures from a 1911 enthusiast that can help illustrate.  

With a frame loaded 1911, the round travels up a ramp formed by the frame, and a cutaway in the lower part of the barrel.  

With a ramp loaded 1911, there is a ramp that guides the bullet in to the barrell. As a result, the barrel does not have the same cutaway on the bottom, and offers a few more millimeters of more support to the loaded cartridge.  These difference in this support to the cartridge is the differentiation between a "supported chamber" and an "unsupported chamber". 

http://38super.net/Pages/supported.html

The extra support is more expensive to manufacture, but can can make a difference in the accuracy of the firearm at longer ranges.  One wouldn't find a sniper rifle, for example, with an unsupported chamber, but there are shorter range rifles that can be found without a feed ramp that offers a fully supported chamber.

At shorter ranges, the mechanical differences of an unsupported generally not a key factor in accuracy or ease of load, and are often easier to manufacture.

Both loading mechanisms are safe.  A "kaBoom" or case rupturing is caused by ammo that is not in spec, or by a barrel obstruction (most common cause is not properly cleaning the gun after its been fired), or both.


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## lklawson (Sep 8, 2009)

A very good summary of the term and usage.

Peace favor your sword,
Kirk


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## Rich Parsons (Sep 8, 2009)

SJC said:


> I have heard about the potential dangers of an unsupported chamber in some pistols. Even with the understanding that this problem is rather rare and often an issue more with a specific round than the gun, it makes me wonder: is the unsupported chamber an issue with handguns only, or do the pistol caliber carbines have the same designs? Maybe the question is, is the unsupported chamber a characteristic of handguns, or handguns calibers?


 
A major manufacturer in their Gen III frames, stretched the 9mm for the 0.40 Cal, and used a complete new design for the 10 mm and 0.45 Cal. 

While shooting this firearm, with over the counter ammo, it went Kaboom in my hands. I believe there is a problem, but as I have only my experience and lots of loyal users of the firearm brand, I left it out to not make it an issue of the specifc firearm (pistol) but the general topic. 

I believe the chamber did not close completely and when the primer was light the explosion sent energy our the barrel as designed but also down into the frame and out any whole possible including some new ones.


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## Carol (Sep 8, 2009)

I hope it didn't make any holes in you in the process Rich!


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## Rich Parsons (Sep 8, 2009)

Carol Kaur said:


> I hope it didn't make any holes in you in the process Rich!


 
I had gun powder and small bits of plastic in the top layers of my skin, but nothing pierced. 

I was wearing none shooting gloves, as they where weight lifting gloves with padding in the palms, and I really think the small cushioning helped a lot.

Of course, my hands were numb and I was working on survival mode in shock for the first few minutes after the event. 

I wa able to place the weapon (* what was left *) onto the shooting cloth and turn to the owner of the weapon and say, "I broke your gun." He replied, "It is a ** which is a hammer you can't break them." 

Later he handed me a revolver and said,  "This is a rock try this one, and leave my favorite guns alone." Of course he was doing the ribbing that guys do to each other. I had already gave him money to buy a new one. The manufacturer did finally fix it, and he returned the money, but I insisted upon paying for the shipping.


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