A Brief Primer on KB's

Discussion in 'Valuable Info' started by WalterGA, Sep 6, 2004.

  1. fabricator

    fabricator Got Biodiesel?


    KaaaaaaaaBooooooommmmmmm! It is when something causes a firearm to make like a hand grenade, they can but seldom do cause serious injury, much is made of it on the internet, but it is really much ado about very little.

    Wanna kill these ads? We can help!
  2. cw2go

    I can understand the confusion. Way back when I wrote up the original description (over 2 years ago, although there were a few recent additions/edits, it is mostly what I wrote the day it happened), I simply indicated all those items I thought might be involved. In the (considerable) intervening time, I have listened to and tested other ideas. Dean pointed out that "reading" primers was not a reliable measure of pressure. I originally balked at this, but it is a good point -- I was comparing primers of different, unknown brands. If I had reloaded the ammunition myself, and used the same brand and batch of primers (and shells, and slugs, etc.) then I would have a handle on more variables. But that is not the situation -- different primers, cases, and powders were all involved, and the primers that appeared more flattened may be softer primers. So that is just one data point in the analysis. I did not know the G19 could fire without being fully in battery, but testing shows I can move the slide a little, perhaps 3/32" (not exactly "tight against the barrel"), which I think may be enough to allow the case to set back slightly and blow out near the rim, as in the photos. Newer Glocks apparently will not do this, I'm told, and I have new parts from Glock to install to (hopefully) remedy this. Yours may not do this, but mine can.

    So what do I think happened? I think it was the cheap plated slugs (which appeared to be jacketed, but I got fooled), which were slightly irregular, may have shaved off just a bit of metal into the chamber neck area and reduced my headspace. And/or the cases might have been slightly oversized. And the round let the slide close enough to discharge, but not quite enough to go to "full lockup" -- maybe 1/16th short -- and this -- possible combined with a slightly hotter charge -- allowed the slide to move back slightly more at discharge, and to blow out the side of the case in the unsupported area. It's just my theory, but I have had a long time to look at all the evidence, and I think it is the most probable cause. I may be wrong, but it has never had a problem with factory loads, and I have fired well over 1,000 rds (of white box Win 115 gr solids) in IPSC matches since then, with no changes other than replacing the damaged parts, so I have confidence in it, although I now know about and have received all the Glock "upgrade" parts, so these will go in before I do much more shooting.

    The bottom line to all of this: you can parse my words, and others can come up with creative new definitions of what a kB! really is, but that's just talk. It doesn't solve anything. What is productive is if people do their homework and check to see if their Glocks need the upgrade, and get it done if they qualify. And they can check to see if theirs can discharge with the slide set back over 1/16" or so. And they should avoid lead or plated slugs, Federal ammo (at least for 9mm and .40), and reloads (unless they are *very* experienced and can control tolerances quite well). Maybe those precautions are not necessary with the new ones, and maybe not if you put on a better barrel.

    I'd like to see people get the word, because Glock has not done a recall and NEVER tried to get the word out that people they need this "upgrade". I didn't know. I had NO idea this was possible (although I have seen perhaps 100 or more notices about Remington safeties and Ruger SA safety upgrades). The precise reason it happened is not certain. How to keep it from happening is pretty well known. So the productive focus is on getting the word out to other Glock owners rather than (as it happens) trying to correct people on different boards who want to reintepret what happened as being something different, or to try to redefine what a kB! as something else, or to say there is nothing to worry about -- that rubs the wrong way. (The language here is not "evolving", it is being misused, hijacking a term to exclude events which it specifically includes. And I don't need a high-speed camera to tell me it didn't stay locked up long enough, and it isn't supposed to blow pieces out in your hand and leave me feeling like I forgot to let go of a firecracker. That was some pretty powerful "contrary evidence" that it didn't stay locked up long enough.)

    But the message is to pay attention and stay safe, since Glock refused to recall the affected pistols, and just isn't getting the word out. What happened, happened. If any of you guys need the "upgrade", get it (go to the web site I listed a few days ago in a prior post for details) -- and tell Glock that responsible corporations get the word out to their customers BEFORE they have a catastrophic event, not after. Let them know what you think of their policy of saving a few bucks by calling a recall situation an "upgrade" to prevent it from blow pieces out in your hand and disabling itself in the process.

    -- cw

  3. CW -

    First let me thank you for taking the time to explain and re-clarify.

    So often these discussion degenerate into name calling and personal accusations - rather than a rational review of the facts.

    I agree folks would do well to insure that their guns are well maintained and in good working order.

    Also, it is both true and a good point that you have much more experience with your gun than anyone else has had.

    When you pull the slide back that 1/16 of an inch doesn't the barrel just slide down the incline in the locking block?
    Does it really move away from the breech?

    The reason that I keep coming back to this point is that about a year ago I tried to make my G35 40 cal fire with a gap between the barrel and the breech.

    I started with an empty 10mm. case.
    It is the same diameter as my .40 but with a larger primer and is of course a bit longer.

    I then got a Lee case trimmer.
    I would put the case into the barrel and try to close the gun and get it to fire.

    I could never get the barrel to even start up the ramp in the locking block - until the case was short enough to allow the slide to close completely.
    Based on that experiment it just seems more likely and simpler that the pressure exceeded the case's strenght.
    Especially since the failure occurred in the unsupported part of the case and not all around the case.

    I dont know if you can try something similar with the 9mm.

  4. cw2go

    Phil - You are correct in your undertone that none of us *really* knows, we are all justa trying to figure this out, and many of us are just trying to contribute clues and assemble facts, which was what my original write-up was for.

    You are approaching the slide lockup question from a different direction. I just tried moving the slide slightly to the rear (simulating a case which was not fully seated) until the trigger would no longer give me that characteristic Glock click. Yes, the barrel drops at an incline, and does not make a big gap at the breech, but I think if you are starting ANYWHERE short of full design lcokup/closure, the slide will begin moving earlier, expose slightly more case, and the unsupported area on the case then may give way. kB!

    This is just my theory after spending hours with inspection lights and trying to see just how the thing could fail like that. And (based on early reports that Glocks had no problem with hot Israeli, +P, and CorBon-type ammo), and considering they must contain a proof load, the pressure theory didn't seem to be a good fit. Incomplete lockup did. That was a puzzlement until I went back to examine the ammo I bought, and found that the "jackets" were suprisingly irregular. After some discussion on another board (Battlerifles or Amback, I think), it was suggested that this was not really jacketed ammo, just plated. Bingo!! That's what it looks like -- that, or the world's most wavy, irregular jacket. I know on some firearms, like M1As, Garands, and BM59/62 types, reduced headspace can cause interesting problems that look like something else. This happens when the tiny shoulder at the chamber neck cruds up. This sounds like a possible. Others thought the casing was not properly sized, but Glocks chamber is "military" oversize. I don't think it was the chamber, I think it was the slug, where tolerences are less precise with a cast slug getting an imprecise jacket, you have the option for tiny shavings to accumulate at the neck. This prevents complete lockup of the slide (probably a bad term, since it doesn't really lock like a rotating bolt would...), which exacerbates the unsupported chamber issue. If there was higher than normal pressure, this could also have been a contributing factor.... Again, these are only theories, but I suspect it was more than one thing that led to this, as these are thoroughly tested arms, and very few -- even of this earlier generation -- have had any problems.

    -- cw
  5. skar

    Have a g17(and love it) and would like to get a .40 or 10mm
    ? how are the sigs on kabooms.?
  6. Joe D

    Joe D Guest

    They will all blow up if double charged/over charged. Bullet set back will also cause a gun to blow.
  7. The tests I did - (with a case (10 mm) that could not fully seat in my .40 cal)
    indicated that if the case is not fully seated, then the breech cannot close against the barrel.
    And the slide cannot go up the incline.

    Try it and let me know what you learn...
  9. the question now is: are glocks more prone to "case failure's" compared to other pistols bcos of its unsupported barrel, tendency to fire out of battery etc.?

    2nd question: in the event of a case failure, is the damage to a glock more catastrophic compared to other pistols? i have personally seen a case failure on a taurus "all steel" pistol, and i think its slide stop just came loose, guys at my club blamed the brass/shell, it was a "pmc" shell.

    thanks in advance:)
  10. Quail Fat

    Quail Fat Member

    Upgrade, smupgrade.. That won't fix a piss-poor chamber. The problem is simply the Glock chamber walls are too thin and the tennifer surface hardening makes it brittle.. The 40 Glock chamber is simply a reamed out 9mm chamber, the 45 chamber is simply a reamed out 10mm chamber.

    When other brands of polymer guns kaBoom, the chambers don't blow apart like the Glock. Other brands of polymer guns have a lot thicker chambers.

    Bullet setback, lead in the barrel or a double charge of powder, when combined with a thin chamber is a receipe for disaster.

    Good luck finding a picture of an XD or H&K chamber than has failed.

    Here is a picture if my XD-40sc chamber. Notice how thick it is and how it supports the case. If I did have a kaBoom, my reciever would be trashed, but at least I won't have to worry about shrapnel from a grenaded chamber exploding in my face. Now feild strip your 40 caliber Glock, insert bullet into chamber and take a look at it..

    I'd like to see somebody take a similar photograph and post it on this forum. It's a design flaw, and nothing will convince me otherwise.;b
  11. Quail Fat

    Quail Fat Member

    Here is a Glock chamber for comparison with the above post.
  12. I think it's sad that this has to be sticky. There are no conclusions in this entire guide that an individual of reasonable intelligence, and minimal education shouldn't be able to reach on their own. Yet some won't accept facts that contadict their beliefs-- unless they are presented in a manner which requires sufficient hoop-jumping in the form of occasional usage of terms that they learned in school. This seems to be how they(individuals of reasonable intelligence who think themselves superior to genius) determine that you are on par with their grossly exaggerated minimum level of reasoning set to determine whether or not a view is fact or fallacy, regardless of the tangibility of their own original belief *cough Dean Speir cough*.
  13. I shouldn't say too much about Speir, as if it weren't for his kb! page's liberal use of anecdotal 'evidence', and general Glock bashing(consisting primarily of lies- not even bent truthes just made up on the spot information almost as if the 'Brady Campaign' manages his site and 'research') with frequent references to GlockTalk Forums, I would have never found this place. Kudos to Speir for introducing me to you guys!
  14. I have Several Glock pistols and love them.
    I carry a Glock 23 Daily and would bet my life on one.
    With that said, I do think a Glock is more likely to KB than other pistols.
    Just look at the other forums.
    Do they have a KB sticky?
    Almost everyone I know (People who do alot of shooting that is)have had or witnessed or know someone who has had a KB with a Glock at one time or another.
    If you use good ammo, It is HIGHLY UNLIKELY you will ever have a problem with a glock.
    If you shoot reloads, LEAD or FMJ, you run a Greater chance of a KB with a glock than with a sig, beretta ,hk or 1911.
    I know some who reload all the time for Glocks without problems.
    But you better be careful with Brass selection etc. (AMERC) for one.

    If I carry one, I must not be too worried about a KB!
  15. BeBop

    Appologies in advance ... What does KB stand for?
  16. KA-BOOM
  17. Lead in a barrel may or may not cause a problem in some handguns, bullet setback sure can raise pressures and double charges of certain powders will almost always cause problems. Have never personally seen a blown Glock, heck I just bought my 1st one, a Glock rebuilt G-23, but I have seen some Single Action and double Action revolvers blow from what I assume were double charges. Did see one S&W M-36 with a blown cyl. due to what looked like a blockage in the bbl. With as many Glocks out there as ther are I am not surprised that some have failed, the question becomes is it a flaw with the gun or what was being fired in it. Saying it hase not happened to an XD or HK is just foolish, at best.
  18. Quail Fat

    Quail Fat Member

    You won't find an XD or an H&K chamber that has ruptured, however there are a lot of Glock chambers that have burst. :)

    Again, you won't find a picture, nor has anybody reported a ruptured XD and/or H&K chamber.

    Glock chambers are thin, loose and sloppy. Look at the picture, the XD and H&K has the best support and has a thick chamber wall.
  19. You won't? An XD or H&K can't be blown up by a serious overpressure event? As Walter would probably say, "horsehockey!" Do you know any more funny stories?

    Thick or thin, put too much pressure in that chamber and it WILL blow!
  20. fabricator

    fabricator Got Biodiesel?

    Send me one of each and I'll blow it six ways from sunday, I have personally seen a head separation in an hk that trashed the frame, the same would happen in an xd, and as far as burst chambers are concerned the stronger the containment the stronger the bomb.


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