What Might Cause a Shotgun to Explode?

what might cause a shotgun to explodeOperator Error

I won’t address this particular event directly other than to say that there’s probably more to this than meets the eye and I will simply add my two cents worth to the subject of guns “blowing up” in general.

Thanks to the Internet, Winston Churchill’s observation that “a lie is halfway around the world before the truth gets its trousers on” is more apt than ever.

I have seen top quality guns self-destruct, but every one I’ve witnessed or examined was caused by operator error.

For example, a competitive shooter had two identical 1911s built for his game and carried both – along with their ammunition – in his range bag; one was in 10mm and the other in .45 ACP. Well, he learned that you can load a 10mm into a .45 and that the 10mm round drops in far enough that you can also chamber and fire a .45 ACP round.  The gun acted like a hand grenade and he lost two fingers and a thumb!

Another Example

Next, I was at an IPSC match when one guy in my relay was shooting the (then) new GLOCK Model 22 in .40 S&W. I noticed that the gun’s report and recoil seemed excessive and he was also experiencing malfunctions.

I asked him what the problem was. He told me that this was his second GLOCK Model 22, as the first one had “blown up.” He added that, after he sent the gun along with his lead reloads to GLOCK USA, the company replaced the gun and told him that

  1. His reloads were overloads, and
  2. Not to use reloads.

I then asked him what he was shooting this day. He replied with a grin, “I’m shooting up the rest of that batch of reloads!” Needless to say, I found another relay.

Someone Up There Likes Me

I’ve been lucky, I guess; I’ve never (knock wood) had a firearm self-destruct in my hands. I’ve fired junk reloads with high primers; fired 9mm in .40s and .380 ACP in 9mms; and I’m also still trying to break the habit of catching a live round when I clear a gun. This last one was reinforced recently when I cleared a fired – but not extracted – case from a “Baby” Browning .25 ACP.

The magazine had four more rounds in it. I retracted the slide, but the case would not eject. I then worked the slide firmly and managed to get the next round to feed while the empty case still failed to eject.

Since this model uses the firing pin to eject empties – well, the feeding round fired. I only had part of my hand near the ejection port and caught a small piece of brass in the base of my thumb. The point is: I’ve been using this gun for over 30 years without a problem, but it happened. (And, yes, I was wearing shooting glasses.)

Another Point to Consider

One last cause of that might cause a shotgun to explode: 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 “push back” can occur with but one chambering since it is dependent on how well the case was crimped or sealed to the bullet.

How many of us regularly chamber and rechamber the first two rounds of our carry loads? (Also, this chambering and ejecting chews up the case rim, which can cause a malfunction. If you are limited to how much ammo you are issued, after cycling the first two rounds a few times, strip the mag and load these first two rounds first so they are last up in the stick.)

The point of all the above is that I think, given enough exposure, “stuff” happens – and we, collectively, are very reluctant to admit to operator error. I also think that, unless H.P. White Laboratories or another lab with an equally sterling reputation does the investigation of a suspect gun and its ammunition, any conclusion can be subject to question.

Stuff Happens

I get a fair amount of new guns each year and, yes, they sometimes do break during my testing and evaluation. Some of these problems have included sights falling off and the breakage of triggers, trigger springs, magazine catch springs, safeties, magazines and slide stops.

I’ve been accused of having a “black thumb” and, no, apparently most gun companies do not “cherry pick” gun writer samples. I received one gun with a shortened firing pin, modified so that the gun could be displayed safely at a trade show. Another, a shotgun, came disassembled and uncleaned in its hard-sided case, with some parts missing!

But, in 20 years, none has “blown up.” This is directly attributable, in my opinion, to my firing (except in some specific torture test circumstances) only factory new or remanufactured ammo and inspecting every round that goes into the gun…and luck. (The four friends who generally help me with the testing are also habituated to inspecting the rounds as they load them – and they watch me, as well.)

Check Your Factory Ammo, Too

what causes guns to explode

As is the case with a firearm, you can buy factory ammunition which is defective, and thus make your shotgun to explode.

Of the ammo sent directly to me, I’ve only found a few with missing primers. I have found more serious defects in large (25K and up) bulk purchases of training ammunition made by agencies when I was either training there or writing about them. I doubt there is a firearms instructor who does not have a desk drawer or a coffee can full of bad rounds. I don’t think this means that someone is getting low bid stuff, but, simply, that given the large volume, the statistical probability of finding a bad round is increased.

Having said this, the defects included missing primers, no primer flash hole, raised or high primers, a split empty case, the bullet seated backwards, a bullet falling out or pushing back in the case, squib loads or loads with no powder or too much powder. All these are factors that could make a shotgun explode.

I’ve even had a case crushed on one side, or mispacked boxes, such as .380 ACP rounds mixed in a 9x19mm box. I’ve also had the empty case separate at the base of the case with what felt like normal recoil from the round fired. (An enlightening quality verification test is to load a 30 round mag with a given brand and run this in a gun on full auto. You hear and feel the ammunition variation if it’s there.)

The Cheap Merchandise

If you must go the “surplus” route, you’re on your own. Ask yourself, “Why is it now surplus?” Most governments have established a time line for their munitions and get rid of it when the dates run out. Like canned goods in your cupboard or prescription medications, there’s a good reason for expiration dates.

My criteria for using foreign made ammo is simple; I figure if I won’t drink their water, I won’t shoot their ammunition. Alternatively, when you are considering a particular brand, simply put the name of the country in the following statement, “_______ quality control.” If you grin while thinking or saying this, don’t buy or use the ammo!

Hot Loads

Not surprisingly, I’ve found that not all ammunition, even if manufactured correctly, will work in all firearms chambered for the caliber. Use a +P+ load in a pistol not designed for this particular load and it will malfunction. Note that some gun companies list the bullet weights and velocities that will (or will not) work in their product. (The information can be found in that often ignored and unread instruction book!)

Poor or No Shotgun Maintenance

Another point to remember is that failure to maintain your firearm can cause it to disassemble itself. Guns designed without a hammer depend on the recoil spring to lock the slide closed without the extra help of an exposed and spring driven hammer.

The spring has to be changed on a regular basis, not unlike oil changes in a vehicle. If the slide fails to close completely, it is possible to still fire the round and have a catastrophic failure. Handguns also fail to close based on debris in the action. There’s one brand of ammo whose copper primers flake and are deposited in the firing pin channel, as well as other areas, in a GLOCK.

For the old-timers, do you remember how a small piece of lead in the revolver’s cylinder crane would make it hard to cycle or close? This same small piece in the barrel seating area of most modified Browning designs will make the action sluggish – hard to open or close.

No One’s Perfect

Now, does all of this mean that no gun company has ever sent out a defective gun? The answer, of course, is no; otherwise, how could end users have gotten a gun which had a barrel with no rifling or a with the wrong caliber barrel attached? There’s still a debate about one handgun which had a change in the steel being used in its slides.

The company claimed this made no difference, but these were the only guns which had a slide separation problem. They might be telling the truth. The cause might well have been some other manufacturing error which had not been acknowledged. In this litigious society, to admit any error is to open yourself up to a lifetime of lawsuits and what gun company is going to take a chance in the civil courts given the overtly hostile climate regarding firearms in general?

After All of That

Despite all these precautions, shotgun barrels still explode. If you get a slightly high or soft primer, coupled with debris in the firing pin channel which holds the pin forward and coupled with tired springs, you will get an out of battery blowup.

If the user simply retards the slide motion by virtue of his grip, the same thing can happen. Guns are mechanical devices which can (and do) fail, as does ammunition. While both are made by highly dedicated and skilled workers, either is still subject to human error. Check the ammo, maintain your firearm and plan for a failure so that you’re far less likely to have one!

Larry Pearson is an NRA certified pistol instructor and a member of the American Society of Law Enforcement Trainers, as well as a former police officer, former military firearms instructor and lifelong student of the martial arts. He also felt that he had something of value to share with the firearms community, and wondered which gunzines he should approach with the above essay. The problem was that he was dealing in ideas and concepts, and virtually all of the present gunzines only want articles about products and services so that their advertising department can sell space and everyone can make money. This is the American way. This is his first published work.

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