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I have always been leery of the Glocks because of their unsupported chamber but never heard of a case failure because of it. I was at a friends house yesterday and we were talking about it because he is a Glock owner. He pulled out a case and showed me that had a hole in it just about the head. It was shot in his brothers Glock. They had to tear down the weapon and do some maintenance on it but were able to get it firing again. I will stick to my SA's.

Sorry, they were shooting .40 S&W reloads.
 

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Awesome! Might want to give a little more info as to what gen Glock it was shot in? Maybe over charged round as you said it was a reload? I have shot thousands of rounds through Glocks in all calibers and never had a case separation. Have many Glocks and not afraid to defend my life with one!
 

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It is my understanding that pretty much all semi auto pistols have unsupported chambers to some degree, even 1911s. The early Glock .40s were a little more unsupported than some others but that issue was fixed 15 or so years ago. The main reason for KB in older glock .40s from what I understand is people trying to use cast lead bullets with polygonal rifling causing too much pressure. I would assume that this would not be a problem as long as the cast bullets are hard enough. Modern Glock chambers are supported just as much as an XD, Berretta or just about any other semi auto pistol or at least that is what I understand to be the case.
 

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It is my understanding that pretty much all semi auto pistols have unsupported chambers to some degree, even 1911s. The early Glock .40s were a little more unsupported than some others but that issue was fixed 15 or so years ago. The main reason for KB in older glock .40s from what I understand is people trying to use cast lead bullets with polygonal rifling causing too much pressure. I would assume that this would not be a problem as long as the cast bullets are hard enough. Modern Glock chambers are supported just as much as an XD, Berretta or just about any other semi auto pistol or at least that is what I understand to be the case.
Picked up a couple of .40 cases at the range yesterday and they have the "Glock Bulge". No idea who shot them or what Gen the gun was but I have found quite a bit of .40 brass that were bulged in that manner.
 

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https://en.wikipedia.org/wiki/.40_S&W#Case_failure_reports

Case failure reports[edit]

Beretta 96 Feed Ramp

The .40 S&W has been noted in a number of cartridge case failures, particularly in older Glock pistols due to the relatively large area of unsupported case head in those barrels, given its high working pressure.[SUP][24][/SUP][SUP][25][/SUP] The feed ramp on the Glock .40 S&W pistols is larger than on other Glocks, which leaves the rear bottom of the case unsupported, and it is in this unsupported area that the cases fail. Most, but not all, of the failures have occurred with reloaded or remanufactured ammunition.[SUP][26][/SUP] Cartridges loaded at or above the SAAMI pressure, or slightly oversized cases which fire slightly out of battery are often considered to be the cause of these failures,[SUP][26][/SUP] which are commonly referred to as "kaBooms" or "kB!" for short.[SUP][26][/SUP] While these case failures do not often injure the person holding the pistol, the venting of high pressure gas tends to eject the magazine out of the magazine well in a spectacular fashion, and usually destroys the pistol. In some cases, the barrel will also fail, blowing the top of the chamber off.
 

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https://en.wikipedia.org/wiki/.40_S&W#Case_failure_reports

Case failure reports[edit]

Beretta 96 Feed Ramp

The .40 S&W has been noted in a number of cartridge case failures, particularly in older Glock pistols due to the relatively large area of unsupported case head in those barrels, given its high working pressure.[SUP][24][/SUP][SUP][25][/SUP] The feed ramp on the Glock .40 S&W pistols is larger than on other Glocks, which leaves the rear bottom of the case unsupported, and it is in this unsupported area that the cases fail. Most, but not all, of the failures have occurred with reloaded or remanufactured ammunition.[SUP][26][/SUP] Cartridges loaded at or above the SAAMI pressure, or slightly oversized cases which fire slightly out of battery are often considered to be the cause of these failures,[SUP][26][/SUP] which are commonly referred to as "kaBooms" or "kB!" for short.[SUP][26][/SUP] While these case failures do not often injure the person holding the pistol, the venting of high pressure gas tends to eject the magazine out of the magazine well in a spectacular fashion, and usually destroys the pistol. In some cases, the barrel will also fail, blowing the top of the chamber off.
I believe it was an issue in Gen 2 Glock 40's.
 

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One of the other things that I have read about these, I wish I could remember where I saw it and I am too lazy today to go looking, is that a common problem being the seating of the bullet into the case. With the short casing and the longer, heavier bullets it does not take but a few hundreths of an inch to go from a safe level of pressure to an unsafe level. The article, also, mentioned that it wasn't always being seated too far in the manufacturing step but if the crimp isn't tight enough the bullet can be pushed deeper in just by loading and unloading the same round into the chamber. I wish I could remember which article it was so I could give you more accurate information, especially since I am getting old and I might be remembering things wrong. I am eagerly awaiting the age to be old enough to sit on my front porch and yell at the neighbor kids.
 

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It is my understanding that pretty much all semi auto pistols have unsupported chambers to some degree, even 1911s. The early Glock .40s were a little more unsupported than some others but that issue was fixed 15 or so years ago. The main reason for KB in older glock .40s from what I understand is people trying to use cast lead bullets with polygonal rifling causing too much pressure. I would assume that this would not be a problem as long as the cast bullets are hard enough. Modern Glock chambers are supported just as much as an XD, Berretta or just about any other semi auto pistol or at least that is what I understand to be the case.
You're right on the semi autos having an unsupported chamber to some degree. Otherwise you'd end up with a 3 point bind. There is a percentage of case that is considered acceptable.

The interesting thing though is how much the barrel of a Glock angles upwards when the slide is all the way back. You'd think that would help cut down on the ramping of the barrel chamber itself.

Sent from my iPhone using Tapatalk
 
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