The purpose of this thread isn't to be contentious relative to this frequently misunderstood subject, but rather to offer a little rational thought and a few facts. (Particularly for the newbies who might have been influenced by the Internet Ignorami) First, whether a pistol, eg., Glock, has a supported or unsupported chamber is generally irrelevant to the subject of KB's. While an unsupported chamber might contribute to a case failure, a case failure does not constitute a KB. So, what's a KB, then? Well, to me, a KB results in catastrophic failure of either a pistol's barrel or slide, or both. A case failure will probably result in a damaged mag, mag release, trigger assembly, maybe even a damaged frame. (or, in the case of 1911's, shattered grips) In order for a case failure @ 6 o'clock to cause a KB, one would have to accept the premise that such a failure would cause dramatic increases in chamber pressure. Does anybody really believe that a RELEASE of pressure @ 6 o'clock will increase chamber pressure? Ever take h.s. physics? If not, or if you failed h.s. physics, then perhaps you should try writing for a gunrag or sponsoring a specious internet site. Let's use an analogy for the purposes of demonstrating the silliness of blaming lack of case support for KB's. Ever fill up an air tank? Ever wonder what happens to a steam boiler or water heater when tank pressures exceed the tanks' pressure maximums? Well, if the tank has a pop-off valve or other method of releasing pressure, not much happens. With no such relief mechanism, a lot happens, catastrophically. Get the analogy with pistol chambers? If you don't, then, well, good luck with your life. Photos of blown-up pistols on websites prove nothing, nor make any statements about the design features of that particular blown-up pistol. The picture might just reflect the statistical quality control anomaly of a factory round, or it might indicate an overcharged reload. The posting of a picture or anecdote on the internet doesn't give one any facts at all regarding KB's. (Even if the photos are of G21's blown up by police officers) There are, I believe, over 2 million Glocks alive and well worldwide. If, as is claimed by the uninformed, Glock's design causes Glocks to randomly explode, then we'd certainly be hearing of more than just a few random cases of exploded Glocks on the internet. Nope, if design flaws were the problem, we'd be seeing tens of thousands of blown-up Glocks, government-demanded recalls, and not just the few "examples" that are posted here-and-there. Now for my own anecdote. I've fired somewhere in the vicinity of 150,000 rounds of my reloads through my Glocks, mostly through G21's. Matt, of CGR, and others, have fired many times more of their reloads through their Glocks than I have through mine. I reload my .45ACP's until the necks split. I've never even had a 6 o'clock case failure, let alone a KB, using a factory Glock barrel. I did experience a KB with my original G21 (see photo), using an aftermarket barrel, powder that was too fast, bullet that was too heavy, and a little of my own carelessness mixed in. Clearly had a feedramp bullet setback, with the expected KB. Please note that the case is split down its entire length. If this had been a 6 o'clock blowout, the case would only have failed @ 6 o'clock. Glocks are among the safest pistols in use today. They are not subject to an abnormal risk of KB. If you overcharge, or, especially, doublecharge a round or use an overcharged or doublecharged factory round, your pistol, regardless of manufacturer, will probably KB. It's as simple as that.