Author Topic: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION  (Read 27811 times)

HAWKFISH

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GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« on: March 19, 2008, 11:02:04 AM »
After being an avid GLOCK shooter for years, I have learned a lot about them. I have shot thousands  and thousands of trouble free rounds without any problems or Ka'booms. What is a KaBoom you ask? Perhaps you don't know. Well here is some info that might help to clear up some confusion. I have copied and pasted 2 Kaboom articles that explain pretty well the jist of the Glock Kaboom. They came from www.glockfaq.com .... That is a good Glock informative website that one can learn a lot about Glocks at. Most Kabooms can be prevented! Glock owners can shoot reloads if you change your barrel or if you load the right way and clean you barrel. Anyway.. hope this helps shed some light on some false info out there.

#1--------------------------------------------------------------------------------
Glock Kabooms...Myth or Not? - MarkCO

I have read the reports where folks say they have 500, or even 5,000 rounds through their Glock with no problems. That is nice, but by no means is it significant scientifically.
I bought the first Glock .40 the local gunshop sold and started shooting IPSC with it. That first G22 went about 23K rounds before it failed. The reason it failed, and documented by myself through exhaustive metallurgical testing, and concurred with by Glock, was due to overpressure caused by lead bullets. Funny thing is that, as I write this, sitting right here at my desk, is a page full of numbers, numbers that luckily I recorded prior to the failure. I was shooting over a Chronograph when the gun blew and had over 120 rounds individually recorded. Each round had been measured and each powder charge individually weighed. I know EXACTLY what the loads, powder charges and velocities were. I look at the numbers now and wonder how I did not pick up what was occurring. But hey, I was young. This was almost 10 years ago.

As I write this, I have a G22 with over 80,000 rounds through it, a G35 with over 15,000 rounds through it, a G27 with over 20,000 rounds through it and I sold a G24 with 15,000 rounds on it, a G23 with 6,000 rounds and a G35 with 2,000 rounds on it (does not count since a KKM barrel) So I have fired 159,000 rounds of .40 through Glock factory barrels.

I have pressure tested lead bullets fired in actual Glock barrels with controlled test conditions and the same loads fired in conventionally rifled barrels. Then I fired jacketed and copper plated bullets in the same conditions to test for pressure increases there. Conclusion is that lead bullets, yes, even the 24 BHN variety, increase pressure after only a few rounds fired. When the pressure reaches an unsafe level has to do with the powders pressure curve, temperature, bullet hardness, bullet grain structure. Weak cases do let go, but do not result in the same type of damage.

When a Glock is overpressured, the shooter is rarely injured beyond a few cuts or bruises on the shooitng hand, none that I have seen have been permanent. And how many have I seen? To date I have personally inspected over 40 blown Glocks that were the result of overpressure. I have reviewed documentation on over 120 others. And, yes ALL calibers were represented.

And how would I know what I am doing, besides just being a shooter? I am a forensic engineer (mechanical) who investigates accidents and failures for a living. I have been qualified in court, as an expert (which is not easy these days). And for the record, the firm I work for does more defense work than plaintiff work. We work for who hires us and, sometimes, our clients do not like our findings, but that is the breaks, facts are facts, evidence is evidence.

Glocks are not perfect, nothing man-made is, but I trust my life to their reliability. I reload (couldn't afford to shoot if I did not). For me, I choose to shoot plated bullets which cost me a few dollars a thousand more than lead. I save on the cleaning stuff and the cost is about the same as lead. I also use the factory barrels, exclusively now (I sold my KKM barreled G35).

The overwhelming majority of blown Glocks are from lead or poor quality reloads. A few are from bad factory loads and a few from defective aftermarket parts. I must beleive that there are a scant few that have had manufacturing defects, but I have not seen one yet that casued a KB. If I do, Glock will surely be hearing from me, and I believe they will do the right thing.

Hope this helped.

#2--------------------------------------------------------------------------------
Glock kaBOOMs - MakeMineA10mm
The original Glock is the 17, and it was designed around the 9mm cartridge package. It is completely and totally engineered to be absolutely safe with that round, and the 9mm seems to be the Glock with the least kaBOOMs, even though it has, by far, the largest number of pistols made for it's caliber (world-wide -> in the US, the 40 is catching the 9mm, maybe even surpassing it). Why is this so?

Well there are many reasons. Ammunition problems are a primary concern, however there is also firing out-of-battery, lead bullets, unsupported chambers, and other factors. To break it down, we have to look at how the Browning locking design works, and this takes quite a bit of explaining.

First, assuming a properly chambered and functioning cartridge, the following occurs:

1. The firing pin hits the primer and the primer/powder ignites.

2. The rapidly expanding gas propels the bullet into the barrel and simultaneously swells the brass case into the chamber walls obturating the breach.

3. The barrel and slide begin moving rearward, in a locked-together position for approximately 3/32 of an inch.

4. How soon and quickly the slide/barrel unit begins moving is determined by the force of the round being fired compared to the inertia of the slide/barrel unit. The heavier the slide/barrel and/or the lighter the force of the round being fired, the slower the slide/barrel open and move.

5. As the slide moves rearward, it is compressing the recoil spring.

6. Just after the bullet leaves the barrel and pressures rapidly drop in the chamber and barrel, the cam on the barrel begins it's thing. This causes the barrel to drop downward, out of it's locked position.

7. The slide continues rearward, without the barrel, and the extractor is hanging onto a segment of the case rim, thereby extracting the now-spent case.

8. The slide, near it's end of rearward movement, draws the empty case into the ejector and the case is pivoted out of the grasp of the extractor and out the ejection port.

9. The slide stops.

10. The recoil spring returns the slide to battery, with the slide's pick-up rail stripping a fresh cartridge out of the magazine and feeding it into the chamber in the process. (The feeding of the cartridge is another process altogether, and doesn't have to do with kaBOOMs, so I'll not refer to it further.)

This leads us to question several things, in a certain order about kaBOOMS:

1. Look at ammunition first, because there's a lot less going on with it. It's either defective in excessive pressure, or weak brass, and that's about it. Two things to check makes it much easier to point at/eliminate first.

2. Look at the bore of the pistol. I have in my possession a Beretta 92 barrel that swelled up when a round was fired immediately after a squib load left another bullet in the bore, obstructing it. It is also relatively easy (in some cases) to see if the bore was obstructed in some way, which lead to the kaBOOM.

3. As a last resort, we have to look at the mechanics of the firearm. This is last, because it is complicated, with many things happening simultaneously, and therefore not an easy yes/no test.

By becoming familiar with the above description of the Browning system and looking at the barrels and slides, you can figure out for yourself, that the metric Glocks (9mm and 10mm) are stronger and safer Glocks from a couple points of view:

1. Barrel walls are thicker on 9mms than 40S&Ws. They have the same outside diameter, but the 40 has a 1mm bigger hole bored through it. Likewise the 10mm and 45 have the same O.D., but the 45 has over a 1mm bigger hole bored through it. Thicker walls means safer.

This is especially true with the 9mm/40S&W comparison. The 9mm, 10mm, and 40S&W all work in the same pressure area: ~35,000 p.s.i. The 40 has a MUCH thinner barrel to contain the same high pressures that the 9mm does with its much thicker barrel. This is not such a big factor with the 10/45 comparison, because the 45 can compensate a great deal for that thinner barrel by operating at lower pressures (~21,000 p.s.i. for +P loads). (This is counter-acted when people convert 45s to wildcats such as the 45Super/40Super/400Cor-Bon, taking away the advantage the 45ACP enjoys here.)

2. Slide mass. Slide/barrel mass (a.k.a. weight) is what gives the slide/barrel unit the inertia to keep from opening too early. The thicker barrels for the metric caliber Glocks, already referred to above, contribute some of the additional weight, but mainly it comes from the weight of the slide.

In the 40/9mm I have not compared slide mass, so I will not comment, other than to only say that, on my 9mm Glocks, I can see that the slide walls are full-thickness for only about 1-1/2 inches forward from the breachface, and I must assume that 40 Glocks have full-thickness slide walls all the way to the muzzle. Still, this will barely compensate for the difference in barrel weight, which means, IMO, slide velocity is excessive in 40S&W Glocks. (This is a major part of the reason MarkCO recommends stronger springs, in differing increments, for all Glocks other than 9mms.)

Likewise, in the 10mm, the slide walls are full-thickness all the way to the muzzle, whereas, in my G-21, the slide walls are thinned very close to the breach. If a G-21 had full-thickness slide walls all the way to the muzzle, it wouldn't function reliably as the slide/barrel unit's inertia would be too high.

This is because the engineers have to pick a slide/barrel unit weight that is as close to the ideal for the middle of the road power-level cartridge as is possible, while still giving full safety for the anticipated (SAAMI max) most powerful ammo to be fired in that caliber weapon. (This is why I am very concerned over conversions of the G-21 to 40 Super/45 Super/400 Cor-Bon, because all of these cartridges operate at higher chamber pressures AND higher slide velocities than the highest level the 45+P operates at.)

These inertia/barrel thickness factors only increase your margin of safety. They do not mean that any Glock/firearm are infallible. Any firearm can be made to fail.

The one factor we have not looked at, yet, is the "unsupported chamber".

This, too, is another cause of many kaBOOMs, and it, again, is connected, at least partially, to caliber. For example, if you looked at an engineer's drawing of the 40S&W case, you would see that the web (the area of the sidewall of the case that begins tapering thicker as you get towards the base of the case) starts much farther down the case than the 10mm, which it was designed from. The reason for this was that when 10mm cases were trimmed down to make the first, wildcat 40S&W cases and bullets of 180gr or heavier were seated in them, the case bulged because the heel of the bullet ran into the beginning of the web of the cut-off 10mm brass. Reamers had to be used to shorten the converted cases' web to allow seating the 180gr bullets desired.

When setting up to make 40S&W brass this was a known problem, and to correct it, the web simply starts lower and thickens more rapidly so that it is still the same thickness as the 10mm by the time you reach the base of the case. This is fine, except on chambers which have relatively long tapers to their feed ramps, such as the Glock. What happens now is that a thinner area of the case is over the beginning area of the feed ramp (the "unsupported" area) and with a case that has too brittle brass, or soft brass, or cracked brass, or an over-pressure load, you can have a kaBOOM.

This is complicated by the factor I cited above: Slide Velocity. The higher the slide velocity, the sooner the slide/barrel unit begin moving rearward, and the higher the residual chamber pressures are while this happens. If residual chamber pressures are too high (from say an over-pressure round), and the case is beginning extraction from the chamber, this only aggravates the unsupported chamber problem.

All of this was likewise aggravated, because several companies rushed production of their 40S&W firearms and/or ammunition. Glocks in 40 cal. were out almost simultaneously to the S&W product! Additionally, there are several lots of Federal 40 ammo that are under recall, because they were loaded to the maximum level and proved to not interact well with guns produced hastily (the first 40 cal Glocks). This is why there was such a rash of 40 caliber kaBOOMs when they first came out. Rushed ammo and guns operating at the edge of the safety margin. It was bound to happen.

So basically, what this all means is, that, barring barrel obstruction, and defective ammunition, the safest Glocks are the ones with the best safety margins (thickest barrels and best inertia to power-level of their cartridges, AKA Low Slide Velocity).

To rank them in this quality of greatest safety margin, I would do so thusly:

1. 9mm
2. 10mm
3. 45ACP
4. 357SIG
5. 40S&W
(and then conversion calibers which operate at higher chamber pressures without compensating for slide/barrel inertia:)
6. 400Cor-Bon
7. 40 Super
8. 45 Super

If one plots out the number of kaBOOMS compared to the number of pistols produced in each caliber, I would be willing to bet that that list would be in the reverse order of my list, meaning the 40S&W has the highest percentage of kaBOOMS and then down to the lowest percentage being 9mm.

Sorry this is so long, but attempting to explain complex concepts takes some room. :-) [MakeMineA10mm]

Here are some links to additional kB! info:
Calibers Glock kB! FAQ http://greent.com/40Page/general/faq-kb.htm
Calibers .40 S&W kB! Report http://greent.com/40Page/general/kb.htm
kB! Pics http://glock.missouri.edu/glock/gkbpix.shtml

tombogan03884

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #1 on: March 19, 2008, 11:21:28 AM »
Good info, Thanx.

MikeO

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #2 on: April 18, 2008, 05:52:37 AM »
Pretty reasonable.

My personal experience is a bit different though. The majority of "kBs" I have seen (w all guns) has been w factory ammo.  Not that much reloaded stuff on the ranges I frequent, and/or the reloaders are more careful? ;)

Factory Federal blew up the cylinder of a new Ruger GP100, factory PMC 40 cracked the frames on Glocks and Walthers, factory Armscor blew a case in a Beretta 96, factory Wolf blew a case in a BHP... ya never know?

HAWKFISH

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #3 on: April 19, 2008, 09:00:51 AM »
Yeah, I know factory ammo causes kaboom's too. However, most everyone only thinks that kabooms happen to Glock.. usually with reloads. I'm glad to see that someone else out there realizes that kabooms happen to other gunmakers too.

gunman1911

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #4 on: May 02, 2008, 08:46:55 PM »
Yeah, I know factory ammo causes kaboom too. However, most everyone only thinks that kabooms happen to Glock.. usually with reloads. I'm glad to see that someone else out there realizes that kabooms happen to other gunmakers too.

Oh yes my friend  you are quite right with that I had a new .45 and bought 500 rounds of factory ball to break it in  and on round 22 the slide came apart at the rear of the ejection port,came of the rail and into my face! >:(
Back up guns---Better to have and not need than to need and not have!

Sponsor

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #5 on: Today at 06:07:51 PM »

Solid

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #5 on: May 02, 2008, 11:18:18 PM »
I think people believe this happens to glocks only, but I have seen; 1911s, HKs, S&Ws, you name it.

Ksail101

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #6 on: May 03, 2008, 12:58:35 AM »
Thank you for all this info. I have known about them and I have heard all the jail house lawyer talk about them. It is good to be able to really get an understanding.
Did we win???

HAWKFISH

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #7 on: May 03, 2008, 04:39:36 PM »
Yeah somone once said, "Information and Knowledge are the turn-keys for life."

MikeO

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #8 on: May 07, 2008, 11:07:43 AM »
An alpha to omega example:

Haven Police Ditch Glocks After Two Explode
Two of 90 Glock Model 37 pistols blew up in separate training incidents a year apart.

http://www.theledger.com/article/20080313/NEWS/803130481

To be fair:

Ammo Maker: Our Bullets Blew Up Guns

http://www.theledger.com/article/20080314/NEWS/803140389

The fix?

Haven Police May Get New Pistols

http://www.theledger.com/article/20080401/NEWS/659628187

More new Glocks in the old 45.

Ocin

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Re: GLOCK -"KABOOM INFO"- HELPFUL EXPLANATION
« Reply #9 on: June 19, 2008, 04:05:52 PM »
This is complicated by the factor I cited above: Slide Velocity. The higher the slide velocity, the sooner the slide/barrel unit begin moving rearward, and the higher the residual chamber pressures are while this happens. If residual chamber pressures are too high (from say an over-pressure round), and the case is beginning extraction from the chamber, this only aggravates the unsupported chamber problem.


Hi Hawkfish,

I think this is an interesting piece, however, i have 2 questions. If they are dumb questions, feel free to yell at me, since I am not all to familiar with the inner workings of firearms.

1) Glock uses a recoil operation, though may it be redesigned by John browning, but isn't it so that with a recoil operated handgun, the recoil and thus the action starts the moment the bullet leaves the barrel, so by the time the slide/barrel/chamber starts to move the pressure has already dropped. Am I correct in this assumption or am I mistaken?

2) In case I am mistaken, wouldn't it be so that the shorter the barrel, the more reliable the gun will be and have less risk of producing a kaBoom as you described, since, the shorter the barrel, the sooner the bullet is out, dropping the pressure?

Thanks for your time.
Ocin
Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest.
Gandhi, An Autobiography, p. 446 (Beacon Press paperback edition)

 

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