I've read everything I could locate on the Glock kB! topic and even done some physical inspections and measurements. My conclusions:
There is reason to suspect that Glocks kB! less frequently (incidents per 100,000 rounds fired, for example) than other guns, but the total number of reports is greater because there are so many of them in circulation. Plus, I suspect that Glock shooters have higher ammo consumption than most others (save IPSC & IDPA junkies).
The problem with Glocks could be severely reduced or perhaps eliminated by either making them "disconnect" sooner (a simple slide modification), or by making the slide travel 1/8-inch farther backwards before the unlocking cams engage (not so simple). Once this is done, all kB!s would truly be from really, really bad overpressure reloads.
Shifting the feed ramp back so the chamber diameter is uninterrupted by the ramp at the case wall area *should* be possible without compromising reliability. It would take only 2 mm of change, which could be negated by shifting the magazine well back 2 mm as well.
One thing: I'm curious about all of these cracked chamber stories. Are there fluid dynamics factors involved which would allow a chamber to crack easier when there is a case wall failure? How does the Glock minimum chamber wall dimension compare with the Ruger P- series? Those withstood the totally plugged barrel and Proof load test, with dramatic brass failure and nothing worse than blowing the extractor off.
Has anyone done a similar destructive test on any of the Glock series?
My final conclusion is that there *is* something fishy going on. It's painfully reminiscent of the almost impossible to replicate "slamfire" blowups with M1s and M1As--the partially locked bolt events which crack the stock and mess up locking lugs.
There is reason to suspect that Glocks kB! less frequently (incidents per 100,000 rounds fired, for example) than other guns, but the total number of reports is greater because there are so many of them in circulation. Plus, I suspect that Glock shooters have higher ammo consumption than most others (save IPSC & IDPA junkies).
The problem with Glocks could be severely reduced or perhaps eliminated by either making them "disconnect" sooner (a simple slide modification), or by making the slide travel 1/8-inch farther backwards before the unlocking cams engage (not so simple). Once this is done, all kB!s would truly be from really, really bad overpressure reloads.
Shifting the feed ramp back so the chamber diameter is uninterrupted by the ramp at the case wall area *should* be possible without compromising reliability. It would take only 2 mm of change, which could be negated by shifting the magazine well back 2 mm as well.
One thing: I'm curious about all of these cracked chamber stories. Are there fluid dynamics factors involved which would allow a chamber to crack easier when there is a case wall failure? How does the Glock minimum chamber wall dimension compare with the Ruger P- series? Those withstood the totally plugged barrel and Proof load test, with dramatic brass failure and nothing worse than blowing the extractor off.
Has anyone done a similar destructive test on any of the Glock series?
My final conclusion is that there *is* something fishy going on. It's painfully reminiscent of the almost impossible to replicate "slamfire" blowups with M1s and M1As--the partially locked bolt events which crack the stock and mess up locking lugs.