Sig P229 Kaboom

[robpete]

That would suck for sure. I would like to know why it happened.

Me too. He decided to send it into Sig as is. Not sure if they'll be able to make a determination, but I'll definitely report back with an update.

[DX250]

I will share my suspicions as to what may have contributed. I recently was shooting my Sig p229 in 357 Sig ( NOE 358-128 sizedto .357 BAC lubed propelled by 7.5gr power pistol and a Tula sp primer) and I had a fail to eject, while clearing the gun I saw the brass that was left in the gun, bulged around the web and most pronounced at the feed ramp and and no neck at all just a little bit of the shoulder. Upon a some investigation the gun will fire out of full battery all be it just slightly. I could set off a primed case with the slide 1/16~3/32 out of full lock just enough for the barrel to just start to drop but still locked. I believe what happened in both my and the OP's case was some thing kept the slide slightly back allowing premature unlocking of the slide while under high pressure and in the OP's case rupturing. This finding got me thinking as to the safety of my P229 so I took a look at my other semi autos and found all but one exhibited the same thing including my girlfriend's Glock 32. The only gun that did not show any barrel movement was my custom 1911.

[35remington]

grey, that's not it either. If the gun is "partially in battery" it will stay that way until the bullet is gone.

The key word in your examination is "still locked." If the gun fires locked, it completes the travel of the bullet through the barrel locked. Once the bullet leaves the gun may unlock and not before........not ever.

The gun will not "prematurely unlock under high pressure." It simply cannot drag the gun's barrel out of battery when the locking surfaces are engaging under high shear forces.

Again, if the gun starts the firing cycle locked, it completes it locked. A better understanding of automatic pistol function would help many properly diagnose such events. Unlocking under high pressure ain't in the cards.

[35remington]

What's more probable......that every handgun manufacturer has a ticking time bomb just waiting to explode in this litigious age, that out of battery firing is impossible to prevent despite the usage of locked breech pistols for over 110 years now and they still can't get it right, that an automatic pistol can disengage its lugs and come out of battery despite high shear forces preventing it from doing so, or............something was wrong with the ammunition?

Some time ago Handloader's Digest had an article (referring to gun blowups) entitled "It Isn't Always Handloads..........But That's The Way to Bet!"

Throw in rechambering factory loads and seating bullets deeper, and something wrong with the handload or bullet seating IS the way to bet in the vast majority of these instances. Out of battery firing or unlocking under very high shear forces is not possible.

People want to believe they are not at fault and someone's mechanical device failed......but people are the most fallible thing of all, and when they are involved, human failure is most probable, by far, of the possible scenarios.

[DX250]

I do fully understand the design and function of an auto pistol, as I said the gun was already starting to unlock therefore the normal requirements to unlock the gun were compromised. The cam in the barrel lug was in contact with the locking block in the frame. The barrel was not fully making contact with the locking surface in the slide. The feed ramp was not setting on top pf the locking block preventing the barrel from dropping (unlocking) at the time of firing. I would like to ask how by brass came out of the gun the way it did if the gun was locked until there was no pressure in the barrel? If I can find the brass I will post a picture. I believe it has gone to the scrap yard.

I do believe the root cause of the fte was caused by an over crimped round not allowing it to fully chamber. I was showing how faulty ammo/ excessively dirty gun can add up to a KB.

[ElDorado]

I suggest you and your buddy carefully examine the remaining rounds from that batch for any discrepancies, starting with those discussed - deep seating, bulge, bad crimp, and don't discount an over-charge just because he used a powder check. Those can fail, too, just as most mechanical devices can. I would take them all apart and check everything.

I'm glad he's OK.

[35remington]

grey, what you're missing is that the actual pull on the barrel to force the gun out of battery......absent gravity, which is what you see working when the gun is empty and is irrelevant to this discussion.......does not occur until the bullet is gone. The gun is specifically timed so disengagement occurs after the bullet is gone. A little out of battery matters not one bit.

Further, positing that the gun unlocks easily, or at all, when thousands of pounds of pressure are ensuring the shear forces holding slide and barrel in battery when the bullet is in the barrel are very high is not very logical. The barrel and slide are very, very actively resisting disengagement. And the barrel won't come out of battery when it is in such a state given it was in battery to begin with. If you believe in such a thing then your understanding of how pistols of this sort work is indeed incomplete.

If the pistol starts the firing cycle locked, it completes it locked until the bullet is gone. Can't happen any other way.

In your examination of how your pistol functioned, you admitted that the gun still had substantial locking engagement if the trigger drops the firing pin. That's the only way the gun can or will fire with a pull of the trigger. That's a gracious plenty to prevent unlocking while the bullet was in the barrel given the very high forces holding barrel and slide together.

Unlocking under such conditions is impossible.

[DX250]

35 I will ask you to reread my last and respond accordingly. I understand the specifics of the timing, as stated in my situation the at the point of firing the timing is not starting from 0 it is already in process. The slide is slightly back and the barrel is not fully locked, gravity has nothing to do with it, bolt thrust is overcoming the sheer force on the slide surfaces and in my situation because the lower locking lug (ie the feed ramp resting on the locking block) is not locked. The sheer forces are not what keeps the gun locked, the lower locking lug that prevents the gun unlocking.

A locked breach pistol should not be capable of unlocking with pressure in the barrel under normal circumstances, that is not what we are talking here just the opposite. We are talking exact right circumstances with something preventing the gun from fully locking all locking surfaces causing timing problems.

I just ask that everyone make sure their loading practices and QC is sound to keep bad ammo out of guns and in bullet pullers.

[dtknowles]

Somewhat familiar with the 229 and 40, would love to see the case. I think that will tell the tale. ............Another theory that makes sense is that some guns just blow up, we'll never completely know why. I'm not a fan of the latter.

I don't buy the "some guns just blow up, we'll never completely know why." theory, the reason may elude us but the reason is there to be found. I to would like to see the case and I would check the disconnector. I had a Kaboom in my HighPoint carbine due to "fired out of battery" no damage to the gun or shooter but the case head split for 270 degrees, barely attached. Some disconnectors can get stuck and some are not tuned to great enough precision.

Tim

Tim

[W.R.Buchanan]

Once again 35 Rem has the correct take on "out of battery firing". WE discussed this just last week in the Glock Kaboooom thread.

There is a few other factors preventing this. One is the firing pin safety which most guns now have. Glocks will not allow the firing pin to travel forward when the slide is as little as .020-.030 off completely closed. the gun is still locked up at this point anyway and remains so until the slide has traveled back at least .100 from completely closed. That is the point that the barrel lug drops below the slide opening and the gun is officially "out of battery."

I do not know for sure, but would be willing to bet, that the Sig has the same kind of safeties engineered into it.

The most probable cause of this blow up is either a bullet push back, caused by either a poor crimp or repeated chambering of the same round,,, or a bad case. By " Bad Case," I mean one that has been reloaded too many times, previously severely bulged and not throw away, or just blind luck of having a marginal case re-index itself into a previously fired position thus subjecting the same weakened portion of the case to another hit.

Quit with this "Out of Battery" argument. It just isn't happening.

The crimp on a .40 S&W case should be .417-.418. If it is more than this the bullet is not crimped properly and it will move.

Also for those who don't think that crimping is necessary and that case neck tension is enough to hold the boolit in position, Flatly put,,, You are wrong ! , and eventually it will catch up to you. If crimps were not necessary, then why is it that every single Factory Loaded Round made,,, is crimped?

Also simply put,,,The .40 S&W is the worst possible round to use when testing your theory.

Randy

[35remington]

grey, I thought read your last post and responded appropriately, addressing each point completely. Nevertheless, I'll try again.

The main point is you supposition is impossible. I'll use the comments in your last post to make my point.

"The slide is slightly back and the barrel is not fully locked,....."

What needs to be understood is the amount of locking engagement that is present when your gun allows you to drop the firing pin with a pull of the trigger is vastly ample to allow the gun to stay locked until the bullet exits the barrel. Most of the engagement is still there, and it's that way for a reason.

" the timing is not starting from 0 it is already in process."

This literally does not matter as long as the gun is fired with a pull of the trigger. Remember that the gun unlocks AFTER the bullet is gone in normal operation, and even if the gun has a little running start on backward slide motion when the trigger is pulled because the barrel is only mostly in battery, the gun is timed such that the bullet is out of the barrel most likely, or very nearly out of the barrel. The gun is set up to fire with a pull of the trigger only when it is safe to do so, and when ample locking engagement exists to allow safe transit of the bullet out of the gun with no issues with case blowout.

The pressure in the barrel is low when the bullet is at the end of the barrel because the peak of pressure is when the bullet is very near or still coming out of the case when the gun is fired. Even if the gun could unlock when the bullet is at this point, residual pressure is so low it is incapable of blowing out the case in any fashion. The case would be very little, if any, out of the chamber, and the brass likely would not even bulge, much less blow out.

What you have yet to explain is how the gun can tug the barrel out of battery when it's pressurized.

"bolt thrust is overcoming the sheer (sic) force on the slide surfaces......."

No, bolt thrust, which is the backward movement of the cartridge against the breechface driving the slide backward, is causing the shear forces on the locking surfaces of the gun, in combination with the bullet and the pressure behind it driving the barrel forward . Bolt thrust has nothing to do with unlocking the gun. Only keeping it locked. Once bolt thrust is gone, the gun may unlock, and not before.

I'll let you try to guess what takes the barrel out of battery. It's not bolt thrust. The forces keeping the barrel in battery when fired are greatly higher than the ability of the pistol to take the barrel out of battery when it is in this pressurized state. That's the great stumbling block for your theory, but there are others as well.

"The sheer forces are not what keeps the gun locked, the lower locking lug that prevents the gun unlocking."

It is at this point the evidence that you don't know how the pistol works becomes pretty clear. The pistol has no lower locking lug because there's nothing to lock to. The bottom of the slide is open, and the movement of the barrel and slide is away from the slide stop pin, which isn't connected to the slide anyway. It is impossible for the bottom of the barrel to lock slide and barrel together because there is no place they contact on the bottom of the barrel.

There is one place where barrel and slide locking occurs, and it isn't the bottom.

The shear forces mentioned are what keeps the gun locked, and the locking surfaces are the top of the barrel and the front of the ejection port on the slide. They lock nowhere else because they contact nowhere else when the gun is fired.

The "perfect circumstances" for the barrel to unlock while the pressure is high do not and will never exist when the trigger is pulled. You proved that better than I could by noting the gun will not fire when the locking surfaces (which are the top of the barrel and ejection port in the slide and nowhere else) are not engaged. It will only fire when the locking surfaces have adequate engagement and not at all when they do not have adequate engagement. .

If the gun is only a little out of battery and the trigger falls, the locking engagement is adequate because the locking surfaces have greatly adequate engagement........still. Reread the above for the "why." Remember that the barrel is impossible to pull out of engagement when pressure is high, and the timing makes it impossible for the gun to even attempt to pull the barrel out of engagement when the pressure is high.

Even if it has your "running start" which isn't much and still falls short of explaining a blowout. You'd still have to explain how it can pull it out of engagement when the shear forces are high, and you haven't attempted to do that.

It won't fire when the engagement is too little or nonexistent because:

It has a firing pin block that prevents the gun from firing when it is too far out of battery, AND

The striker is out of reach of the sear when the slide is a certain distance back. This last feature does not require the proper function of the gun to work to prevent out of battery firing.......it will prevent firing even if the firing pin block fails.

I think that covered pretty much everything.

There is always an inverse correlation between the belief in case blowouts due to "out of battery" or "early unlocking" and knowledge of how pistols work. In other words, the less you know about how pistols work, the more you believe in "out of battery firing" or "early unlocking."

I have yet to find an exception to this in these discussions.

[35remington]

W.R., thanks for the corroboration. It is much appreciated. You posted just before I did and I'm rehashing some of the points you went over for the reason I didn't see your response, but that's what happens on forums sometimes.

My interest is in diagnosing events correctly, and that is best done when events are properly accounted for. Then the more likely causes can be more fully examined.

The "out of battery" and "early unlocking" arguments are dead and always have been, and it takes a lot of bandwidth to refute them...........but good information is sometimes worth the effort of explanation.

[W.R.Buchanan]

And they just keep a comin' !!! Mainly because people dont' really understand how the guns work.

Randy

[MtGun44]

Double charge, NOT out of battery - that is almost impossible, even though folks continue
to claim it. Everyone is always looking for some other reason, but get a good mirror
and take a look.

Stop wasting time on the gun and start studying your reloading process to stop putting
two charges in the case. Yes, I DO understand what the powder check die is SUPPOSED to
do, and somehow it failed. Spend time figuring out HOW. I've seen many of these and
watched folks spin their wheels for various periods before they buckled down and worked
on the root cause - somehow the process of putting powder in the case went wrong. Wrong
powder, wrong setting are possible but the overwhelming majority are just two times as much
as you wanted. I have done this myself - ONCE about 32 years ago and still work VERY hard
to make sure it never happens again.

I know of ONE out of battery firing, loading a .44 Automag by dropping a round in the chamber
and dropping the bolt. Firing pin spring was failed and when the extractor slammed into a stationary
cartridge rim THAT COULD NOT MOVE - unlike a round in the magazine - the firing pin inertially fired
the primer. Hammer can never reach the firing pin until locked.

How do I know that one was not a double charge? Because the normal charge of H110 totatlly
filled the case, slightly compressed. Destroyed the gun. By the way - loading that way is STUPID.
I didn't know it at the time.


Bill

[Char-Gar]

When you look at the damaged pistol and weight all the possibilities, the odds on favorite for the cause is an overcharge of powder. Yea, yea, I know it didn't happen, but most likely it did. The more moving parts you put in a machine, the more attention is needed to the process and you can take it from there.

[Fluxed]

Lack of case inspection may be the culprit here.
Its easy to grab up a bunch of "range" brass, clean up and think its 100% ready to load. But you get one case that's not got much (if any) bullet grip and have the bullet jam back into the case when shooting and you might get the result we're talking about here.

I'm loading lots of .45 on a single stage press, so feel each case as I size and expand. On one batch of much fired brass, I'm seeing one out of a hundred, sometimes less, sometimes more, that can't be sized to hold a bullet. I'm culling them out as I go. If I was loading on a progressive, I'd be loading and shooting them. Sooner or later this will catch up to you. And it comes sooner with unknown brass that is not inspected piece by piece.

Loading brass that you've picked up off the ground, or bought from someone else who has picked it up, requires inspection beyond just seeing that its clean and shiny.

[35remington]

What I'm distinguishing is that these users all to a man claim out of battery firing with a pull of the trigger or that the gun came unlocked during firing. Neither event is almost impossible. Both events are completely impossible.

[35remington]

On those guns that lack a slide stop crosspin, a locking block is substituted.

"Aha!" says some. "It locks the barrel when it is fired!" Some here seem to be laboring under that misconception.

No. It has nothing to do with holding the barrel in battery when it is fired. Only the lugs on the front of the chamber and the cutout for the ejection port in the slide do that. If you don't know what it does, the "how" of how pistols function really has eluded you.

[DX250]

I have just 3 responses.

1) My thoughts on the subject are based on the engineer that I consulted on the subject after my near KB. His background is a Masters in Mechanical engineering and a bachelor's in Fluid Mechanics from Georgia Tech and has extensive experience in the firearms design industry.

2) As stated before bad ammo IS the root cause of the KB period, no questions asked.

3) I will put this out there again, I am not even asking for a posted answer just think about it with an open mind, I would like to ask how by brass came out of the gun the way it did if the gun was locked until there was no pressure in the barrel?

I am done.

I just ask that everyone cast, load and, shoot with the highest safty standards in mind also, do not shoot malfunctioning firearm.

[35remington]

grey, your engineer is quite mistaken if those are his assertions you are repeating. Bring him by here to get him up to speed on how pistols really work. He doesn't have a clue.

Bring your brass by and show it to us with a picture. If there is no brass, your recollection is probably flawed. Gun can't unlock until the pressure is gone.