it only costs a nickel to contact winchester to ask.
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it only costs a nickel to contact winchester to ask.
If the barrel and the blown case are still around... I'd love to see it IN the chamber again, but not in the pistol. That will give a very good idea of what happened.
with all this talk of bad ammo, come to think of it, I had a squib load from a box of winchester white box last month. I immediately stopped and field stripped my pistol (cannot remember which one I was shooting ) and checked the barrel to make sure it was clear.
I'm glad I reload my own.... that way, in the event of an ammo malfunction I can keep my nickel and try to a$$kick myself:D
First of all, I checked my CM40 and the case head is fully supported. I guess they respect the .40 more than the 9mm
Now here is what REALLY happened. I had to play with my CM40 a bit to verify this, but I am pretty certain...
What happened is that the gun fired OUT OF BATTERY. I don't know why that happened - dirty chamber, burr on the extractor, rough bolt face, out of spec cartridge, I can not determine what caused it.
But think about how the Kahr works. At the instant of firing, the barrel first drops a short distance. I can't find my micrometer right now, so lets call it 1/8". Until the barrel has dropped the entire 1/8", the case does not move back from the chamber. The barrel drop, or lockup, is what allows the pressure to drop before the case is extracted. By the time the case begins to extract, the bullet is supposed to exited the bore, which equalizes pressure. That is why you get brass, but not clouds of hot gasses and bits of metal out of the ejection port.
I discovered that the CM will drop the striker (discharge) with the barrel dropped about 1/2 way (call it 1/16"). That extra 1/16" is the fatal margin. By discharging out of battery, the timing is off, and the thin case wall will be pulled out of the chamber while the bullet is still in the barrel and high pressure exists. And kaboom, the case wall lets go. In my opinion, that is exactly what happened.
Now think about any straight blowback guns you have. I have a Hi Standard Supermatic Citation. I love to shoot different ammo, but some .22 rounds will leave me with little powder burns on my shooting hand. That is because the springs are calibrated to some form of target ammo, from 30+ years ago. Some ammo will extract before the bullet leaves the bore, spraying gas out the port (which of course is the entire top of the gun since there is no port - the slide simply hits the barrel to form the chamber). If you have shot a Marlin Camp Carbine or something similar, you have probably experienced the same thing - you get hot gasses out of the ejection port because the slide opened too soon.
In the case of a locked breech gun, that should generally not happen, which is one good reason that anything bigger than .380 is usually locked breech. You need that type of action to handle the higher pressure.
I don't know why the gun fired out of battery, I just know it did. The round may not have seated fully in the chamber for any number of reasons, but that is what happened. The round started to extract before the pressure dropped, and of course the case wall blew out at the weakest point. Gas always seeks and vents from the point of least resistance.
The theory is proven by the condition of the primer. It is not flattened. It was not pierced or cratered by the firing pin. It was not blown backwards. All those things are signs of excessive pressure. The primer shows none of those signs. He had trouble getting the empty case out because the 9mm is a tapered case. The front of the case was allowed to expand into too big of a space in the chamber, which plasters it onto the case walls, it was beyond the amount of expansion that it could come back from.
The slam fire was a pretty good theory, the only problem being that it would probably have been in battery when it occurred, and would not have caused the damage.
I had a Garand that would slamfire due to a burr on the bolt. It did it a few times. The gun went bang without pulling the trigger, but nothing was damaged, not even the cases.
So I have no doubt this is what happened. It all fits. He pulled the trigger to fire, there was no squib in the barrel, there was no slamfire, there was no overpressure. For some reason the gun did not go fully into battery, and fired in that condition.
The recoil spring could be the culprit, but so could dirt, or quite possible a tiny piece of brass from the previous round that stayed in the chamber.
I've run across some bad ammo lately. I had two out of 50 PMC .40 rounds that were too big to chamber in my PX4 and one round of WWB that had a 3/16 of an inch or so of the crimp bent back double. That round wouldn't chamber either.
Probably better than a snap cap for surprise practice of no boom drills.
........this thread just gets better and better. Great theory, I like it.
Now the $64k dollar question is determining exactly why it did as your theory suggests.
It's a great theory but I'm not completely sold on it.
Has to be a combination of issues or the planets being aligned so to speak.
I have a K40 that when new would fire out of battery, only slightly out of battery but definitely not a good thing. It ended up going back for barrel peening and they replaced the barrel and slide no charge of course.
I never saw any bad signs carefully looking at the cases etc.
Take slightly out of battery, insert a possibly weak case, an mild overcharge etc and I might buy it full price.
I have had many guns that did not always come completely into battery. .40 for some reason only comes in that flat point range ammo, and it does not always feed smoothly, especially in the Kahr.
But usually pulling the trigger does snap the gun fully into battery. In this case, Not. On my CM, holding slightly out of battery and pulling the trigger feels like it is pushing it into battery, so I am thinking something was wrong with the round or something was in the chamber.
Depends on how much out of battery it is. As well, I assume yours is a .40
The case head is way more supported in the .40 based on photos here and my observations. Therefore, it would take less to have a thinner part of the case extracted too soon. Less distance, that is.