This was a matter of some discussion recently in another thread based on claims that out of battery (OOB) discharges were possible with the SIG P320 and they happen without fault by the shooter. Thanks to extensive work and experiments by Grayguns I believe that incidents due to some mechanical fault of the pistol were conclusively demonstrated to be impossible.

But can the shooter do something in some situations to cause an OOB discharge?

The answer is yes, as demonstrated in this video:
https://www.youtube.com/watch?v=a87zOgkiCYo

Although watching the video is best for the full story, in short the shooter’s magazine evidently failed to feed a cartridge properly (“feeding” is what magazines do), and the round ended up nose down and base up in the magazine. When the shooter attempted to clear that malfunction by slamming the slide forward, the cartridge discharged and caused minor injuries to the shooter’s hand.

Some stills from the video:

This one shows the cartridge visible through the ejection port in the base up position.





When the slide was driven forward, the lower leading corner of (what I call) the “stripper” ridge contacted the primer.





This shows how the primer was pierced by the stripper ridge and discharged the cartridge.





This shows the sharp corner at the lower front of the stripper ridge that pierced the primer.





The man in the incident takes blame for not clearing the malfunction properly; that is, he shouldn’t have tried to get the round chambered by striking the rear of the slide. We might ask, however, whether the usual tap the magazine and then rack the slide procedure would have caused the corner of the stripper ridge to contact the ill-positioned cartridge’s primer as well. I believe it would have, but the force would probably have been less and perhaps not enough the discharge the round. But maybe it could have.

In any event, I believe the incident is something to be aware of. The video shows the shooter having several malfunctions during the firing string, so we might also wonder why and why he continued competing with probably defective gear. But of course that’s only speculation.

As another point, though, the incident brought to mind a bit of SIG P220 history. The pistols originally had a cartridge stripper ridge on the bottom of the breech block similar to the one pictured above. As I understand or recall, an LE agency in Chicago had some unintentional (OOB?) discharges with the pistols, and it was blamed on the same sharp corner. Reportedly SIG tested the guns and were unable to duplicate the UDs. But they still introduced the “Chicago mod” which was to bevel the bottom front edge of the stripper ridge.*

And then there are current SIG P320 pistols. As pictured, both the 9mm and 357/40 slides have small bevels at the point I’ve been discussing. The 9mm slide is on the left and the 357/40 on the right.





Those bevels seem, however, to just be to allow the ridge to fit closely against the feed ramps of their respective barrels. Could they also help eliminate the possibility of the type of OOB discharge discussed above? They seem too small to me for that purpose, but …?


* I’m basing this discussion on my memory. I believe that member Chris Orndorff knows more about that than I do, so perhaps he will add to it.

Glad the shooter suffered only minor cuts. The bevel on that edge would have to be pretty wide to prevent this. Even the gently sloped and shorter corners you imaged could have done this. It would likely need to be at least as wide as the primer cup (in 2 dimensions) to prevent pinching the primer compound between the cup and anvil.

Still seems like it would be rare. It got a damn near perfect center strike on that cartridge primer.

Yea, if it won’t cycle, hit it with the back of your hand or better yet a hammer.

Nothing like evaluating the malfunction.
I thought the tap in tap rack bang was to tap the bottom of the mag not the back of the slide. LOL

His skills or lack there of in clearing the first malfunction it’s evident his training is in matches. Speed first, technique last I guess.

Damn

FWIW, I stopped teaching Tap-Rack-Bang. I taught that jam clearances are nothing more than a speed reload. Drop the mag that jammed, work the slide to clear the bad round. Insert a new mag and rack. No tap on a potential bad magazine or the slide.

That’s a new one to me.

I am not sure I fully understand your position on not teaching tap rack bang (or reassess for the enlightened lol). Seems like thin reasoning since that drill cures the overwhelming number of malfunctions. Your "version" is slower and in nearly 100% of the cases throws away a partially full magazine of fully functioning ammo. I would love to know which LEA teaches your method. Tossing the magazine is basically assuming the worst, a type 2 (? I get the numbers confused lol) malfunction or a bad magazine when statistically overwhelmingly it is just a bad round.

Your pictures made me wonder so I have an LTT Elite sitting on my desk and I took it apart. It had an identical "stripper" ledge (I love that title) so I doubt it is much of an issue. We obviously all have had malfunctions. I can't say I have ever had a round do quite like that before. I think this was just a seriously odd occurrence.

If he had done the proper TRB drill, what do we surmise would have happened? It clearly wasn't under the extractor so would the kaboom happen or just a wicked double feed?

What I see is someone more concerned about looking cool than handling safely. Clearing your round to catch it in midair then holstering as fast as possible. I suspect that’s how that chubby kid had the ND where he holstered and raised his hands to start his stage and *bang*. There’s no race to holster. He’s good, but he’s also cocky.

Couldn’t be bothered to slow down to clear it properly. Sucks he got hurt. I suspect if he hadn’t been hurt, he wouldn’t have learned anything.

quote:

Originally posted by pedropcola:
I am not sure I fully understand your position on not teaching tap rack bang (or reassess for the enlightened lol). Seems like thin reasoning since that drill cures the overwhelming number of malfunctions. Your "version" is slower and in nearly 100% of the cases throws away a partially full magazine of fully functioning ammo. I would love to know which LEA teaches your method. Tossing the magazine is basically assuming the worst, a type 2 (? I get the numbers confused lol) malfunction or a bad magazine when statistically overwhelmingly it is just a bad round.

Not my recent experience. I had a couple of nose up failures to feed, traced to splayed magazine lips. When those were realigned, the problem quit. I had one malf that just left a jumble in the action. I haven't a clue on that one. None would have responded to a TRB and the time spent attempting it would have been wasted.

M. Ayoob cited a trainer who recommended the hasty clear and reload instead of trying to diagnose a specific malfunction and its remedy. Sorry, I don't remember his name or affiliation.


I had not heard of the stripper rail setting off a round in the feedway, but there is no shortage of cases of firing on the ejector. Don't hold your hand over the ejection port when unloading.

quote:

Originally posted by sigfreund:


* I’m basing this discussion on my memory. I believe that member Chris Orndorff knows more about that than I do, so perhaps he will add to it.

Nothing to add really, pretty good memory for an old guy . That bevel is added to what I call the cartridge ram. “Stripper ridge” has a certain flair though!

Jim Watson, with a nose high feed a tap rack bang drill would clear that though right? The round still was under the extractor?

My question still stands. I would like to know if any major LEA or any reputable trainers even that recommend dropping a full mag, racking the slide, and starting over with a loaded mag (assuming you have another which is a whole other reason that this is problematic).

This “method” seems like overkill and bad technique in general. I’m always willing to learn but I will also question something that seems dumb. This seems dumb. Maybe I’m wrong.

quote:

Originally posted by Chris Orndorff:
Nothing to add really, pretty good memory for an old guy

I sometimes amaze myself with what I remember versus what I don’t. And then I think, Nah, just what’s important, and what’s not.

Regarding the throw away your magazine response to a malfunction, I too believe it’s a very odd idea. If a magazine has been used with no problem in more than a little bit of previous training, it’s very unlikely to be the cause of a malfunction. Having seen and personally experienced very many malfunctions over the past 20 years or so, one—count ’em: one—was due to a magazine that had been damaged by being dropped on the feed lips sometime prior to the training session.

The vast majority of failures to fire are due to having no round in the chamber, followed rarely by a dud cartridge. Ejection failures are very rare as well, but when they occur it’s due to an improperly lubed gun and/or weak ammunition leading to slow slide velocity. Low-powered ammo is starting to be more of a problem due to the extra weight of an optical sight on the slide, so that’s something else to worry about. But all those malfunctions are almost always, and correctly, cleared by the tap, rack initial response. A failure to eject can require a bit more vigorous action that sometimes results in the ejection of a live round or two, but seldom is removing the magazine necessary except in drills that involve artificially set up failures to extract.

This is not a P320 issue. This could happen to any gun. Being a USPSA shooter myself and watching him smack the rear of the slide over and over and over throughout the match, I'm not at all surprised that he didn't use proper techniques and methods to clear the malfunction. I'd guess that the gun was either dirty (really dirty), poor quality ammo or poor quality reloaded ammo.

I've seen this exact practice many times in matches. I'm amazed by the fact that some shooters will put up with ongoing malfunctions (as in match after match) rather than diagnose and fix the problem. Often I find that the person never case gauged their reloads and you'll see that type of malfunction over and over.

Sadly playing gun games doesn't always lead to the best training practices for real life shooting skills.

Would love to hear more from the shooter how long this problem was going on, factory ammo or reloads, last time gun was cleaned, etc, etc, etc

Doing malfunction clearing drills at waist level while looking down was my first clue that games are the priority over proper training by a reputable organization.

Unless of course that's another new fangled technique that's taught.

I had one out of battery detonation at MOAC in Paducah, with my P320. It sprayed brass all over me and blew out the side of my frame module. Jerry Jones lent me his P320 to continue the class. I then had a second OOB detonation, a few magazines later. We decided it was ammo related. I traded out the PPU ammo for something else and continued with a 3rd gun, without incident for another 2000 rounds.

Bruce

To try to quash yet another change in firearms terminology, “out of battery discharge” refers to the discharge of a cartridge when the slide or bolt is not fully forward and therefore the cartridge is not fully chambered. In that situation the cartridge can rupture because it’s not fully supported by the barrel chamber and can occur even with standard ammunition and normal pressures.

The term does not refer to having a cartridge rupture due to an excessive powder charge or other overpressure situation that causes the case to rupture even though the round is fully chambered. As Bruce Gray has demonstrated, it is virtually impossible for a true OOB discharge to occur with a P320.

quote:

Originally posted by pedropcola:
Jim Watson, with a nose high feed a tap rack bang drill would clear that though right? The round still was under the extractor?

No it was not. TRB would have had no effect.

quote:

Originally posted by sigfreund:
To try to quash yet another change in firearms terminology, “out of battery discharge” refers to the discharge of a cartridge when the slide or bolt is not fully forward and therefore the cartridge is not fully chambered. In that situation the cartridge can rupture because it’s not fully supported by the barrel chamber and can occur even with standard ammunition and normal pressures.

If the slide of a tilt barrel auto pistol is not closed and the cartridge is not fully chambered, what is to set it off? The firing pin is not aligned with the primer.

quote:

Originally posted by Jim Watson:
If the slide of a tilt barrel auto pistol is not closed and the cartridge is not fully chambered, what is to set it off? The firing pin is not aligned with the primer.

Well, exactly as pertains to the P320 and similar pistols. As I keep saying, Bruce Gray examined other possibilities, but the point you make is one of the reasons it is very unlikely to impossible in normal operation.

But as a general issue, out of battery discharges are possible with other firearms designs. For example, if an AR-15 type firing pin were stuck in the forward position and extending through the bolt face, it could conceivably cause an OOB discharge if enough resistance were encountered during the chambering phase. The same thing could be possible with a bolt action rifle. There are Internet photos of OOB discharges, such as this one:





Then of course it can happen, as discussed above if something other than the firing pin contacts the primer, such as an ejector. But in my previous post I was thinking of an OOB discharge when the cartridge is not fully chambered.

I know about the propensity of the AR to slam fire. One day at the range, the previous relay had two ARs demolished. Both rifles assembled in the same shop, both shooting the same ammo. Hmm. My money is on the ammo, soft primer or high primer reacting to the unsecured AR firing pin.