Glock kabooms,10mm vs .40S&W


Tropical Z
January 15, 2004, 11:04 AM
A recent thread stated that 10mm Glocks werent really a kaboom issue and that it is pretty much a .40S&W situation.Has anyone seen statistics on this anywhere? Seems to me they would be similar in their occurence unless its because of frame and barrel differences.

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January 15, 2004, 11:47 AM
There are differences in the brass also.

January 15, 2004, 11:54 AM
I think most of the Glock kabooms have centered around the 40 S&W. The Glock design offers little in the way of case support and chambers are usually cut to maximum dimensions. The 40 chambers seem to offer the least support, so a lot the brass is left in open air. A number of the kabooms were reported with Federal ammo, evidently their brass is a little thinner than other manufacturers. I expect a great number of kabooms occur with reloads. Not necessarily overloads either, but brass that has been fired in Glocks and has work hardened from expanding to fit the large chamber and swelling in the unsupported areas, then being resized.

Sean Smith
January 15, 2004, 12:04 PM
The main difference isn't case support, since neither the .40 S&W nor the 10mm Glock barrels provide much case support. The difference is the 10mm case vs. the .40 S&W case. Specifically, the 10mm brass has a thicker web area, and so can safely contain higher pressures than the .40 brass can. Yet .40 S&W runs at almost the same pressures as 10mm (35,000 psi vs. 37,500 psi). Furthermore, many 10mm loads being shot, even those that far exceed .40 S&W ballistics, are loaded to less than the max pressure spec for 10mm (this is possible because there is more room in the 10mm case for large volumes of slow-burning powder). Hence under "less than ideal" circumstances you are much more likely to blow up a .40 than a 10mm.

January 15, 2004, 01:13 PM
Buy a Glock in 10mm Automatic and find the Zen in your zone! :D :cool:


January 15, 2004, 11:12 PM
There's also the setback issue in the .40. With the heavy bullets, the small remaining case capacity means that even a little setback can run pressures up very quickly. Since the cartridge is already typically loaded to max pressure, just a little setback can cause big problems. This is especially a problem if it's a reload where the brass has already been fired in a Glock chamber and resized.

January 16, 2004, 12:25 AM
The Glock 20 was designed around the 10mm cartridge, while the Glock 22 was simply upscaled from the Glock 17.

January 16, 2004, 02:37 AM
And, if case setback is an issue, look out for Law Enforcement, because they are constantly loading/unloading their weapons, and likely get new ammo annually (if that). So the non-gunny types in LE will just keep loading and unloading those top two rounds...

And, Glock has a lot of LE contracts...

And a lot of them are in .40 S&W.


Tropical Z
January 16, 2004, 11:18 AM
I forgot about 10mm brass being thicker.

Sean Smith
January 16, 2004, 12:08 PM
Random side note: as the flipside of the bullet setback issue with .40, in some loads with certain powders in 10mm you run out of room in the case before you can reach max loads. An example would be Accurate #9 with heavier bullets, where you basically run out of room in the case before you even reach a max load, and #9 doesn't compress anyway. Even with #7 you pretty much can't double-charge most published loads because doing so would completely overflow the case...

Bullet setback is possible with any caliber, however, including 10mm, and may or may not cause problems based on a variety of factors.

January 16, 2004, 01:51 PM
Glock chamberings experiencing KBs, with .40 in the overwhelming lead. It's interesting, as the two rounds are at opposite ends, really, in SAAMI pressures. However, they are also afterthoughts with respect to their designs orginal chamberings of 9mm and 10mm, respectively.

January 19, 2006, 03:12 PM
I have a question about factory +P ammo for the Glock model 22, .40S&W caliber.
With the Model 22's unsuported chamber, is consistant use of +P ammo in any factory grain weight bullet a hazard?
Especially these lighter bullets such as the 155 JHP+P, and 165 JHP+P.
I never shoot any 180grain factory ammo in my Glock 22.
I don't use +P ammo at all, I only shoot standard 155 and 165 grain bullets, and they are much easier to shoot, and more controlable to use, and with less recoil and muzzle flip.
Does anyone know if the Glock pistol in any caliber, might have a problem with +P ammo of any grain weight bullet?

January 19, 2006, 03:25 PM
The slower the powder/lighter the bullet, the more latitude you have in a setback situation. I reload for 10mm; won't reload .40.

January 19, 2006, 07:33 PM
As far as Federal brass being weaker... Older Federal brass with "FC" on the headstamp was among the thinest near the web area. Federal acknowleded thier problem and improved their deminsions a few years back and is now among the strongest .40 S&W brass. The redesigned Federal brass has "FEDERAL" on the headstamp. FWIW I've put a few thousand rounds of reloaded Federal brass through my Glock, but it has KKM barrel in it.

As far as I know, there aren't any official specs for +P or +P+ in .40 S&W. I don't know of any manufacturers that claim to make it. The .40 is more versitile that it generally gets credit for, though. I have loaded up rounds that I've measured at all the way from 280 ft-lb to 686 ft-lb out of my Glock without going past published max. loads.

January 19, 2006, 09:22 PM
As natedog pointed out, Glock rushed to get into the .40 Smith and Wesson market by making minimul modifications on their 9mms. The Glock 20 was built from the ground up to be a 10mm and everything about it was engineered to take a steady diet of full power 10mm Auto and outlast its owner. It is very durable and surprisingly comfortable to shoot. If you haven't experienced a Glock 20 loaded with Double Tap, you're missing out, IMO.

Glock barrels are pretty high quality. Their chambers are cut loose as a reliability measure but even with the loose chambers, I've seen some pretty good accuracy. And Glocks don't have unsupported chambers either. The feed ramp removes a tiny fraction of an inch from the 6 o' clock position but other than that the Glock offers support on par with most other brands I have seen. Comparatively, the barrel from my Glock 20 is very similar in design to my HK USP 45 barrel, just looser and with a little less support at the 6 o' clock.

I don't really see what the big deal is. If you shoot strictly factory ammo, shoot and be happy. If you want to handload and hover near the upper end of a cartridge's potential, and you feel a new barrel might be safer and extend case life, get one. The Glock is fully on par with name brands like SIG and HK in terms of quality and even with the aftermarket barrel, isn't going to cost any more than them.

January 20, 2006, 01:49 AM
As a mod ofver at GT for years, NEVER heard of or seen a Glock in 10mm ever sustain a kaboom.

I reload a lot of hot loads and I use a 6" KKM target barrel.

Found dozens of cases with splits and cracks. Chamber held the pressure and the rounds went downrange without me even knowing.

Glock upgraded the 10mm barrel for the Glock 20 a couple years ago too.

January 20, 2006, 02:07 AM
I heard of a solution to Glock barrel problems: Bar-Sto

never heard of .40 S&W +P or +P+, never seen any loading data to suggest there is such a thing.

While we're here, strongest cases for .40 S&W? I like Speer, love Cor-Bon (naturally) and will pretty much load anything yellow. Alot of folks don't like to reload the S&W, but I'm a brass-scrounging tightwad.

January 20, 2006, 02:38 AM
The Glock 20 was designed around the 10mm cartridge, while the Glock 22 was simply upscaled from the Glock 17.

And the .40 S&W cartridge, much like the .41 AE, is designed so that 9mm guns can use it with a barrel, slide, and mag change.

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