On the upper, the barrel seems to have taken no damage at all, but the ejector
Monday, March 27, 2017
Glock Mini k-boom
Not sure what caused this weather a barrel blockage or an over loaded round, but there it is. I was lined up on a target at the match, and BOOM I get a really sharp recoil, my mag self-ejects to the ground between my feet, and I've got powder stains on my hand. Here's the casing:
Blowed that sucker clean in two. Here's the lower:
That bent piece of metal with the shiny ends is the slide stop lever, now severely truncated. The Mag was ejected out the bottom and suffered the loss of some of the front of the housing so I need a new Mag and lever.
On the upper, the barrel seems to have taken no damage at all, but the ejector
and the plunger that holds it in place have completely disappeared. Could have been much worse but I guess the modest loads I'm using kept the damage to a minimum. There may be barrel damage as well;
This seems to be hairline cracks, one on each side of the barrel. Additional news as it develops.
On the upper, the barrel seems to have taken no damage at all, but the ejector
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17 comments:
I have seen similar things happen in Glocks where the case had been reloaded a number of times. The unsupported part of the case is weakened By bulging a bit and being resized over and over until the strength is gone. At least that was the best I could figure out based on what the shooter(s) said.
I cleaned the barrel in a solvent tank and put it under a more powerful viewer. Yes, it's cracked. Bummer.
I'm going to agree with A. Nony Mouse. How many reloads on that case?
From what I've read, you can get aftermarket barrels with better case support, but the potential tradeoff is reliable feeding.
And, after some percolation, given the chamber cracks, I'll offer up a double charge. Not sure what your powder charge is for a "modest" load, but I think a modest load can do the blowout, considering the unsupported chamber and multiple reloads on a case, but maybe not the cracks.
Probably several reloads, all to a rather low level but what I saw was not the failure mode for a failed case. Cases fail with a longitudinal split and generally get ejected more or less normally This one had no longitudinal split and had a larger than normal recoil when it went.
I could be wrong, but it doesn't seem like it.
That looks strikingly similar to a Glock kaboom I witnessed some time ago. We later attributed it to a double charge, the previous round having registered on the chrono. It may be worth your while to study that kaboom;
http://blog.joehuffman.org/2015/05/22/pressure-signs/
What you experienced was no "case failure" in the ordinary sense. What you have there is a massively over-pressure event. I don't know the caliber you were shooting, but your language "moderate loads" might leave open the possibility of a double charge.
I don't know, but a good idea is to always try to select a powder that cannot possibly fit a double charge in the case without overflowing. -- Lyle
We did get near 44 magnum energy from a Glock 40 cal. The chrono registered an impressive velocity. So the gun blew up; he hit his target. -- Lyle
Hodgedon recommends 4.5 to 4.9 grains of Titegroup under the 165 gr bullet, .40 S&W. I'm using right at 4.0 grains which is giving me a power factor of 137. The action cycles fine and my hands survive the experience (I have arthritis).
What I suspect is this: My loading press, a Lee 1000, sometimes jams on a misaligned case which requires that I back off on the handle to clear the jam. When this happens I check the next 2 cases for a possible double feed. I will have to change my malfunction drill to something more foolproof from now on. It would be nice if the press included a powder charge check but alas no. I may have to invent one.
Interesting to note that the K-BOOM Lyle cited was in a gun with a Lone Wolf barrel. As it happens I am trying to get one of those for my gun. Best price I've found and seemingly indestructible.
Nah, that'll buff right out.
Extra load bang? Double charge. I'm thinking of moving away from titegroup. It's too easy to miss a charge or end up with a double.
For a while I worked in the automated assembly business and the first thing I learned there was that every other step in a process was an inspection step to insure that the previous step had been done correctly. I designed a reloading press that adheres to this principle as an exercise and found it required some 8 stations, a supply of compressed air, and a PLC controller. Needless to say, I don't have one. Pity that, as it would make perfect bullets every time and notify the operator if anything went wrong.
What you have there is a case head separation. This can be due to overworked brass getting weakened at the web. However, when that is the case, even if it messes up the gun, it shouldn't do anything to the barrel because, if anything, the barrel sees less pressure than usual.
Having witnessed a couple double charges, I would also say you didn't double charge. Since your barrel is still in one piece even if cracked. My guess from the level of damage and having loaded using the lee powder measure that's on your lee 1000, that you had a 1.X charge putting you over pressure. Whatever process you are using to clear press jams, you are probably getting the powder cavity in the measuring disk partially over the powder drop opening in the die.
The main thing is you still have all your fingers & your eyes!
Here's another factor to consider: Bullet setback. Glocks in general, and the small ones in particular, have what I would term a violent loading/chambering cycle.
Soom years ago, I wrote about this subject in their long forum post on Kabooms! in Glocktalk. (I think I joined it around page 15?)
I have a G27 that I used for cartridge chambering tests. Virtually every time a cartridge is chambered, factory or aftermarket, it sets the bullet back to some extent. I suspect the little Glocks would tend to move them more than the larger models, due to the higher velocity of the slide. (lighter weight slide, stronger springs)
No cartridge should be chambered more than once in a Glock, without inspecting the overall length. Reloaded ammo should have a few run through your gun to check for excessive setback, which could be due to lack of case tempering or insufficient crimping, or both.
I measured over 60 thousands setback on the first chambering on some re-manufactured ammo. That sort of result leads to vertical stringing on a target.
I saw the same sort of problems with a batch of .45acp from Blazer Brass about the same time. My friend's govt model would choke on loading it, yet my Officers Model was a 100% loading. But again, accuracy was poor. (Blazer just shrugged off the problem)
BTW, Glock is aware of this subject. I spoke to them at the SHOT Show about this, and they acknowledged the factory is cognizant of it.
Read the manual that came with your Glock...No reloads. No problem...
Glad you still have all your appendages, Bill. Be happy about that. Expensive lesson, but not excessively so.
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