STI Kaboom!

[Krdshrk 3,878]

Saw this on the Brian Enos forums:

Went to the range today to do a few drills, and the 26th shot barrel blew up. does any one now if there is any kind of warranty through STI. This was with PMC factory ammo not reloads. the gun maybe had 1000 rounds through the gun. It bowed and cracked the slide also

[Pizza Bob 1,488]

Pretty poor pictures. Maybe the gun fired out of battery?

[Pew Pew Plates 358]

wait.... I thought that only happened to glocks?

 

 

If it fired out of battery, the chamber wouldnt have blown open like that.

[Sam02S2K 3]

wow....is the guy okay?

[Pizza Bob 1,488]

If it fired out of battery, the chamber wouldnt have blown open like that.

 

 

I thought that might be precisely what would happen - although I guess a case head separation would make more sense for an out of battery discharge.

[Shane45 807]

To bow and crack a slide it HAD to be a serious over charge or some wildly incorrect powder or both. This wont be an STI warr issue, I suspect PMC will be replacing his pistol.

[Pew Pew Plates 358]

I thought that might be precisely what would happen - although I guess a case head separation would make more sense for an out of battery discharge.

 

A seperation also wouldnt cause the chamber to do that. Both a seperation and out of battery would result in everything BUT the chamber from going kaboom, you would actually have LOWER chamber preassures with those situations. Frame ( especially on polymers), magazine blowing out, maybe a cracked slide, etc would result from seperation/ OOB. A case seperating adds no extra stress on the chamber. Think about it...if cases added strength to the chamber/protected the chamber... all black powder guns would kaboom on the first shot! (no cases there!)

 

Shane hit the nail on the head with his above post. The gun fired as it should. The ammo is likely the culprit

[Krdshrk 3,878]

http://www.brianenos.com/forums/index.php?showtopic=128157

 

The guy's ok.

[Pew Pew Plates 358]

Haha it was a .40. go figgure.

[Vlad G 345]

Haha it was a .40. go figgure.

 

That sounds like bizarre comment to me. Double charge any cartridge (factories make mistakes too) and you will get the same result regardless of caliber.

[Pew Pew Plates 358]

That sounds like bizarre comment to me. Double charge any cartridge (factories make mistakes too) and you will get the same result regardless of caliber.

 

 

40 has a rep for kabooming guns. Mostly older glocks which had case support issues (in theory) but the problem is exacerbated by the high pressures.

 

from wiki:

 

The .40 S&W has been noted in a number of cartridge case failures, particularly in older Glock pistols due to the relatively large area of unsupported case head in those barrels, given its high working pressure.[25][26] The feed ramp on the Glock .40 S&W pistols is larger than on other Glocks, which leaves the rear bottom of the case unsupported, and it is in this unsupported area that the cases fail. Most, but not all, of the failures have occurred with reloaded or remanufactured ammunition. Cartridges loaded at or above the SAAMI pressure, or slightly oversized cases which fire slightly out of battery are often considered[by whom?] to be the cause of these failures. Many competition shooters[who?] who reload for the .40 S&W will utilize a heavier than factory tension recoil spring to increase the lock time of the slide and prevent potential issues with early slide lock release. These failures are referred to by many[who?] as "kaBooms" or "kB!" for short. While these case failures do not often injure the person holding the pistol, the venting of high pressure gas tends to eject the magazine out of the magazine well in a spectacular fashion, and usually destroys the pistol. In some cases, the barrel will also fail, blowing the top of the chamber off.

 

 

Beretta 96 Extractor NotchWhile the .40 S&W is far from the only cartridge to suffer from case failures, it is more susceptible for a number of reasons. The .40 S&W works at relatively high pressures (33,000 psi/230 MPa typical, but 35,000 psi/240 MPa SAAMI max). Since the .40 S&W is a wide cartridge for its length, and is often adapted to frames designed for the equally long but narrower 9x19mm cartridge, the length of the feed ramp must be longer to provide the same angle, which causes the feed ramp to extend into the chamber. This in turn leaves more of the case head unsupported. While this is not necessarily unsafe, it does reduce the margin of safety. When exacerbated by out of battery firing (leaving even more case head exposed) and potentially weakened brass (due to reloading) these factors appear to lead to the higher incidents of chamber failure. The number of case failures in the .40 S&W is serious enough that Accurate Arms no longer recommends reloading of .40 S&W cartridges for firearms without complete case head support.[27]

 

In late 1995, Federal Cartridge of Anoka, Minnesota undertook a redesign of their .40 S&W cartridge case to strengthen internally the area of the case web. While no one at Federal, will address this for the record, it has been suggested that this move was dictated by the popularity of the .40 S&W Glocks, and Federal's attempt to hedge against head/web ruptures with any of their .40 S&W ammunition.

 

 

Federal .40 S&W rounds which may contain suspect casings may be identified as follows: Lot number consists of 10 characters (mostly numbers). In the 7th position, there may be a number or a letter. If there is a number in that position, the ammo was manufactured with the old style (possibly defective) brass. If it contains the letter Y (1995) or R (1996), the ammo has the redesigned casing and should be okay. If the letter H appears, then check the next three digits (the last three in the lot number). Ammo lot numbers H244 or below have the old style casings. Lots H245 and above have the new style casings.

 

This information was provided by Federal Cartridge Company in September 1996.

 

Writer Walt Rauch who first brought forth information that bullet set-back such as often occurs in administrative unloading/loading) in the .40 S&W could raise pressures exponentially. Rauch published some specific information on this set-back issue in the May/June 2004 Police and Security News, in a feature entitled Why Guns Blow Up! "The simple chambering and rechambering of a cartridge does push the bullet back into its case."

 

Hirtenberg Ammunition Company of Austria (at the request of GLOCK, Inc.) determined that, with a .40 caliber cartridge, pushing the bullet back into the case 1/10 of an inch doubled the chamber pressure. This is higher than a proof load. This can occur with but one chambering since it is dependent on how well the case was crimped or sealed to the bullet.

 

[Maksim 1,504]

wierd. What about Squib followed by another round?

[Krdshrk 3,878]

Nope - was not a squib. The round had left the chamber.

[Vlad G 345]

40 has a rep for kabooming guns. Mostly older glocks which had case support issues (in theory) but the problem is exacerbated by the high pressures.

 

I know its reputation very well, I've seen a number explode at very close range. What no one tells you is they will ALL explode regardless of caliber. The problem reputation for the .40 comes from the fact that USPSA shooters love it, and shoot a lot of it. Which means reloading, and because of the volume of rounds we shoot, sometimes means careless reloading. The reason you see so many more reports of blownup .40s is because there are so many more .40s being used and reloaded for with very high round counts. I've seen 9's and .45s blow up too.

[Ray Ray 3,566]

Gotta love those STI guns!

 

Pass

[Shane45 807]

There are reasons you see more 40's go. Volume may be one but the other was the poor execution of this caliber in the Glock22. Since the pistol in question is an STI and a double stack at that, it is highly likley that its a ramped barrel with a fully supported chamber. Which would also give some indication that the problem was likely ammo.

[Shane45 807]

Ray, if your going to pass because a sample of 1(and said sample, the pistol is likely not the issue imho), you better sell everything you have including your underwear!

[Vlad G 345]

Gotta love those STI guns!

Pass

 

Have you ever handled or shot one?

 

I get seriously annoyed when people poop on STI's or .40s because competition shooters break them. We break everything, we are the airport suitcase handling gorillas from those TV commercials. Leaving aside what seems to have been a bad factory round which would have likely broken anything, you basically talking about racing hardware under extreme use. It is like watching a car race, seeing a race car catch fire and calling it crap. Take any mechanical device and push it to its limits, feed it extreme fuels, and it will sometimes fail. Competition shooters are fully aware that they may destroy their $3000 guns fed hand loaded ammo with fast burn rate powders like TG, VV220, or Clays just like drag racers know they may blow out their hand built engines fed exotic fuel blends. It is a risk we take.

 

Competition shooting is the experimental lab of firearm design, shooters and smiths tinker with things until the squeeze the last bit of performance, and the results of those experiments end up being production gun features 10 to 20 years later. What every one sells as the 1911 configuration now, was the realm of competition customs 20 years ago. The red dots we slapped on handguns for decades are now appearing as options on production guns aimed at the tactical markets with all sorts of big name trainers "experimenting" with something we've perfected. Same story with the use of red dots and low power variable scopes on rifles.

 

We see a lot more factory guns **** the bed then we see race guns do the same, because just like in car racing you may be very proud of your Mustang or WRX or whatever but when you put it on the track it will eventually eat its own transmission. You can drive it to work and back and never see an issue but push it to the limits and it will fail. The latest Ferrari model has been catching fire lately, will you pass on one because it isn't as good as your Honda?

 

The reason people shoot STI's is not because they the perfect daily driver, it is because they are the best race cars.

[Ray Ray 3,566]

I shot one during the "shore shot vs Bayonne" thread. Don't understand the attraction. Doesn't float my boat. Not to mention it was fininky with ammo.

 

Pass

 

My 19's don't fail.

[Vlad G 345]

I shot one during the "shore shot vs Bayonne" thread. Don't understand the attraction. Doesn't float my boat. Not to mention it was fininky with ammo.

 

Pass

 

My 19's don't fail.

 

Enjoy your Honda Civic.

[Ray Ray 3,566]

Enjoy your Honda Civic.

 

I've never officially owned a Japanese car, I'm more of a jeep guy myself.

[lunker 274]

I know its reputation very well, I've seen a number explode at very close range. What no one tells you is they will ALL explode regardless of caliber. The problem reputation for the .40 comes from the fact that USPSA shooters love it, and shoot a lot of it. Which means reloading, and because of the volume of rounds we shoot, sometimes means careless reloading. The reason you see so many more reports of blownup .40s is because there are so many more .40s being used and reloaded for with very high round counts. I've seen 9's and .45s blow up too.

 

It is true that there are a large number of 40S&W shooters, but guns in that caliber still blow up disproportionately more than those in other calibers. The reason is that 40 is a higher pressure round with less room for error in a semi-auto pistol, much less one with a crappy unsupported barrel. While I have read of 9mm and 45ACP kabooms, I have never seen one like I have a 40. Is it possible that some of what you have seen is from competitors pushing the limits of the brass, their guns, etc? I will say I haven't read about 9mm and 45ACP guns going kaboom with factory loaded ammo. I have for 40S&W though (although it does seem that most involve hand loaded ammo). I suspect if more people handloaded 357Sig (tapered case makes that a PITA), we would see lots of kabooms there because it has an even higher pressure than 40.

[Vlad G 345]

It is true that there are a large number of 40S&W shooters, but guns in that caliber still blow up disproportionately more than those in other calibers.

 

Ok, show me the statistics please. Yes the 40S&W is a higher pressure cartridge, no doubt, but double charging ANY cartridge will results in a catastrophic failure. I think the reason you see so many more .40s blow up is because of its popularity in USPSA combined with the fact the USPSA shooters prefer to use very fast powders which are also often quite compact. For example with something like Titegroup I can fit 3 full chargers in .40 case and still sit the bullet without compressing the powder. In .45 it is closer to 5 full charges. This is means it is a lot easier to double charge a case and not realize you've done it. Fast powders don't give you a lot of room for error.

 

I think there is a bit of overstatement of the rate of failure of the .40s&w per round fired, and yes a lot of those came from Glocks because of their famed "poorly supported chamber". I can smirk at glock shooters that tell me that their guns never break, but in all fairness they were the first to try a gun that size in that caliber with the G22 so they got it a bit wrong. Newer versions have better support. Thats a gun design issue, not a cartridge issue, but somehow people blame the cartridge not Glock.

[lunker 274]

Ok, show me the statistics please. Yes the 40S&W is a higher pressure cartridge, no doubt, but double charging ANY cartridge will results in a catastrophic failure. I think the reason you see so many more .40s blow up is because of its popularity in USPSA combined with the fact the USPSA shooters prefer to use very fast powders which are also often quite compact. For example with something like Titegroup I can fit 3 full chargers in .40 case and still sit the bullet without compressing the powder. In .45 it is closer to 5 full charges. This is means it is a lot easier to double charge a case and not realize you've done it. Fast powders don't give you a lot of room for error.

 

I think there is a bit of overstatement of the rate of failure of the .40s&w per round fired, and yes a lot of those came from Glocks because of their famed "poorly supported chamber". I can smirk at glock shooters that tell me that their guns never break, but in all fairness they were the first to try a gun that size in that caliber with the G22 so they got it a bit wrong. Newer versions have better support. Thats a gun design issue, not a cartridge issue, but somehow people blame the cartridge not Glock.

 

My hearing about Kabooms never came from the world of competitive shooting. It was always on gun boards with recreational shooters, some of whom reloaded.

While I search for statistics, will you admit that there is some logic in thinking that higher pressured ammo is more likely to cause kabooms, premature wear leading to kabooms, etc than lower pressured ammo? Even without any accidental double charges. Especially when the majority of guns in the market that have a chambering in both 9mm and 40S&W were designed for the 9mm and reverse engineered to shoot 40S&W? That might not be the case for guns used in IPSC (don't have enough knowledge about IPSC guns), but I know it is for many standard handguns.

[Vlad G 345]

I will be the first to say that designing a gun around 9mm and then taking some metal out to fit a larger and higher pressure cartridge in it is a pretty terrible idea (Hi G22, how are you today?). Guns designed from the start around the cartridge (M&P, etc) and those designed around larger rounds and then converted (1911/2011) will of course perform better. Most of the failures I see on the internet (instead of in person) have been Glocks.

[raz-0 1,259]

I shot one during the "shore shot vs Bayonne" thread. Don't understand the attraction. Doesn't float my boat. Not to mention it was fininky with ammo.

 

Pass

 

My 19's don't fail.

 

It's all about how it's built. My 2011 eats factory length .40 out to 1.175" OAL ammo. Eats factory power loads, hollow points, powder puff loads down to 118pf. About the only thing it doesn't like is montana gold 155gr hollow points loaded to 1.120. Btu that's a bullet profile issue, NONE of my .40s like it, even my M&P. I doubt glocks would like it any better. Most of the STI problems come about due to competitors running it at the edge of tolerances, or due to 140mm magzines they are trying to stuff maximum capacity in. I've had a remarkable amount of "luck" with arbitrary 126mm magazines with factory springs and followers. Even after stepping on them. Imagine that.

 

As for the glocks not failing.. well, I get to repeat a phrase a LOT at matches. Which is "That's not possible, glocks never break." Even with regards to the 19 I have gotten to say it multiple times (along with ow.. that looks like it hurts when the guy shooting one has reloaded part of their palm along with the magazine). I'd get to say it more, but not a lot of 19s get shot as it isn't that popular for competition.

 

I can tell you that of the kabooms I have seen, the #1 cause is the ammo. Mostly the fault of a new/careless/lazy reloader. The #2 cause is bad DIY gunsmithing causing an out of battery firing. Invariably this is a polymer gun, and to the best of my recollection they have all been glocks and XDs. I suspect that is mostly because you can create an OOB problem by not knowing what you are doing while trying to get a really light trigger on them. An OOB round in a metal gun might screw up the grip panels, but in a polymer framed gun can total the gun. #3 would be simple case head separations. Likely due to questionable brass.

[lunker 274]

I will be the first to say that designing a gun around 9mm and then taking some metal out to fit a larger and higher pressure cartridge in it is a pretty terrible idea (Hi G22, how are you today?). Guns designed from the start around the cartridge (M&P, etc) and those designed around larger rounds and then converted (1911/2011) will of course perform better. Most of the failures I see on the internet (instead of in person) have been Glocks.

 

Glock is a funny company that way. The image of "Glock Perfection" is so strong that minor changes in design occur with no one but the informed few ever knows about it. There is no flyer than ever came out from Glock about improving barrel support. However, if you look at a Gen 1 or 2 40 barrel and compare it to a Gen 3 or 4 barrel, you will notice a difference. There are lots of other minor changes that most other companies would advertise, but Glock will not (i.e. changing the size of the extractor plunger, striker tip profile, etc).

As an aside, I am not a Glock hater. I have owned and enjoyed a few. Just not drinking the Kool Aid, that's all.

[Old School 611]

I could be considered a Koolaid drinker. Lunker is right about GLOCK making changes and that's why I'm on the phone with them from time to time.

 

I understand about the unsupported chamber thing was a problem. I could explain why they thought it was OK but there's no excuse.

 

The thing I don't understand specifically is how messing with a trigger pull could cause an Out of Battery Discharge on a GLOCK.

 

The striker safety plunger blocks striker travel until the trigger is pulled and the trigger bar depresses the plunger.

 

Granted there are alot of hacks that shouldn't be messing with anything mechanical.

 

For example: "The $0.25 triggerjob" I saw a guy polishing a sear on Youtube an while back. OH! OH!

[Shane45 807]

It is my understanding that the real problem with the Glock KB's was with the disconnector. It is what really allowed the OOB firing. It also makes perfect sense to me.

 

(edited to add that Glock does not call it a disconnector but it performs the same function as a disconnector) I am decidedly NOT a glock armorer so I dont know for sure what Glock calls it.

[Vlad G 345]

The thing I don't understand specifically is how messing with a trigger pull could cause an Out of Battery Discharge on a GLOCK.

The striker safety plunger blocks striker travel until the trigger is pulled and the trigger bar depresses the plunger.

 

Yup and right after that the sear puts pressure on the striker which is contained inside the slide which has a light replacement recoil spring, and it moves the whole slide back a bit right before it lets go of the striker. Welcome to the world of Out of Battery Discharge This happens when people replace the standard recoil spring with a lighter one and don't replace the the striker spring with a lighter one as well.