Postman,
You'll find lots of threads here about the Glock KB and unsupported case issue. The most notable handgun to have a partially unsupported chamber is the Colt 1911 series and contrary to popular belief, these guns also have had instances of "rapid dis-assembly", the problem mainly concerns Glocks chambered for .40, .357 and .45, the 9mm's have very few documented instances of KB's. Glock ran the feed ramp into the chamber wall and optimised the overall chamber dimensions and design to facilitate reliable cycling and extraction, and this certainly works. The KB problems are supposedly un-heard of if you avoid the following, reloaded ammo, lead bullets, powder AA#5 and possibly aluminum cartridge cases used on some practice rounds. Many documented KB's with standard pressure original factory FMJ's have been documented however and the argument as to the frequency of case/chamber failure will run forever, most Glock owners believe that it's just scaremongering, or worse, deliberate rubbishing of the new kid on the block. Most people I've spoken to seem to feel that the reloading issue has arisen due to people overcharging the cartridges to +P level or even double loads, but the latter will blow most any chamber, supported or not, and since the Glock is actually designed to function most reliably with +P rounds, this reasoning doesn't seem to scan. Rather, it is more likely to do with the possibility of the already weakened cartridge being fed into the chamber with the previously bulged case seated in exactly the same position, thereby greatly increasing the likelihood of it failing under pressure. Many, many people will tell you here about having fired countless thousands of rounds of every conceivable type of ammo through their Glocks without so much as a stovepipe, a few others will tell you about horrific hand or eye injuries caused by exploding .40's. FWIW my take on the Glock range is this, they seem to fire far to easily for safety with a hammer at half cock, a half inch 5.5 lb trigger pull and no positive (as opposed to passive) external safety, couple this with possible KB problems and a grip angle that makes me point the gun naturally high, and a Glock, at least for now, is not an option for me personally. Like I said before, many other contributors here will vehemently disagree with this appraisal, as will countless thousands of LEO's, but since you asked what the perceived Glock "problems" are, this is my $0.02.
Now remember you Glockenspielers we're all friends here.
Regards,
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Mike H