Is it mechanically possible for a Sig Sauer P320 to discharge without the trigger being pulled?

jscpm · Dec 3, 2022

I notice that Sig Sauer, a manufacturer located near me, is getting sued because people are saying their P320 handgun has a tendency to fire spontaneously--without the trigger being pulled.

I am not familiar with the firing mechanism used in such guns, so I am wondering if, from a mechical point of view, it is physically even possible for the gun to discharge without the trigger being pulled.

I know this is more of an engineering question than machining, but I suspect there are some machinists here that might have some pretty detailed knowledge of the innards of these contraptions, maybe a better knowledge than the engineers in some respects.

Cole2534 · Dec 3, 2022

This has been a point of contention for years. I think the answer is- NO.

There are stories of people, usually cops, getting shot unintentionally with 320's but they largely are in instances of the weapon being handled. IE- glock leg.

Sig released an updated trigger to address this. Ive been shooting these since 2016ish, I have some 320s of old and some of new...none have ever discharged unintentionally.

If I recall correctly the controversy is whether the gun will fire when dropped in a particular fashion. Glock handles this with a lever on the trigger shoe itself, Sig handled it by balancing the trigger assembly. The ultimate goal is to ensure the trigger doesn't cycle purely from inertia or momentum.

This is also when one needs to understand the difference between an ND (negligent discharge) and AD (accidental discharge).

While we're here- none of my AR15s have ever assaulted anyone, regardless of magazine capacity or flashhider selection.

GregSY · Dec 3, 2022

If Alex Bladwin is holding it, yes.

Scottl · Dec 3, 2022

This reminds me of the old Remington 700 trigger controversy. Supposedly a defective trigger design that can cause accidental discharges but everyone I've talked to says these are cases of grossly mis-adjusted triggers despite the clear warnings in the manual against this.

In the case of the wounded cop mentioned above I suspect the cause may have been slippery hands from a powdered donut.

Thunderjet · Dec 3, 2022

Scottl said:
In the case of the wounded cop mentioned above I suspect the cause may have been slippery hands from a powdered donut.

Wow,
Tough room.

Scottl · Dec 3, 2022

Thunderjet said:
Wow,
Tough room.

Hey, I once asked a detective friend if he heard about the dumb robbers who tried to hold up a donut shop. He just groaned and said "Gee, never heard that one before".

Thunderjet · Dec 3, 2022

Scottl said:
Hey, I once asked a detective friend if he heard about the dumb robbers who tried to hold up a donut shop. He just groaned and said "Gee, never heard that one before".

Good friend of mine retired from a local P.D. a couple of years ago after thirty years of service. (he hates donuts BTW)

Couldn't stay away. Got on as a investigator for the local D.A.s office and loves it.

I could NOT deal with the awful shit he has to wade thru.

Those folks that do that stuff are just wired different than most of us.

L Vanice · Dec 3, 2022

In 2018, we passed through Clare, MI and bought a couple donuts at the shop owned by the local cops. Don't know if it was ever held up.

My mother had a 1911 Colt. She never told me who gave it to her, but it must have been before she married in 1932. I learned to field strip it and put it back together with my eyes shut around 1954. No way would that thing shoot if you did not want it to. Browning knew his business. I see that Sig sells 320's with or without thumb safeties, but none have a grip safety or muzzle safety.

Larry

GregSY · Dec 3, 2022

I gotta say...I read cheap, poorly written novels all the time and in almost every one the protagonist (who is a genius, possesses magical computer skills, is a black belt in karate, is a woman, and who is wealthy) shows their prowess by field stripping their pistol and reassembling it after a meticulous oiling and cleaning. It's a religion of sorts.

I also gotta say I have all sorts of pistols and I've never needed to strip any of them down. I also find that they will fire reliably for decades without any sort of cleaning. I do sometimes put some oil on them.

I believe this is why I am stupid, have minimal computer skills, don't know shit about karate, am not a woman, and don't have a pot to piss in.

Doug H · Dec 3, 2022

While I have never seen the inside of a Sig 320, I do know enough about it to know that it can not fire spontaneously. One of the design elements that make striker fired handguns inherently safe, is that they are similar in function to a double action revolver. The act of pulling the trigger is what "cocks the hammer". In a literal, mechanical sense, that isn't a perfect parallel, in function, it isn't far off.

As for the remarks about 1911's being safe, I would say that they can be very safe, or very unsafe, depending on a lot of variables, generally related to guys not knowing what they are doing, the difference between a safe one and a hazardous one is often little more than a couple of strokes of a file. Anyone who has ever fitted a thumb safety knows how little contact there is between the safety and the seer. There is also no shortage of stories of people shooting thru their hand while conducting a press check. It could be said that can't be held against the design of the 1911, and in theory, I would agree, but it is without a doubt the most common platform for amateurs to muck around with, and some of those amateurs have no business changing a lightbulb, nevermind modifying the inner workings of a firearm. If you are not intimately familiar with the source of said 1911, I would assume it to be unsafe, until proven otherwise. For the record, I have owned a couple of those scarey ones in the past, and and a few new parts properly fitted restored them to safe status.

Scottl · Dec 4, 2022

GregSY said:
I gotta say...I read cheap, poorly written novels all the time and in almost every one the protagonist (who is a genius, possesses magical computer skills, is a black belt in karate, is a woman, and who is wealthy) shows their prowess by field stripping their pistol and reassembling it after a meticulous oiling and cleaning. It's a religion of sorts.

I also gotta say I have all sorts of pistols and I've never needed to strip any of them down. I also find that they will fire reliably for decades without any sort of cleaning. I do sometimes put some oil on them.

I believe this is why I am stupid, have minimal computer skills, don't know shit about karate, am not a woman, and don't have a pot to piss in.

I seldom strip pistols down beyond what is needed for cleaning the barrel and chamber. In most cases a good spray with a cleaner/lubricant and then the excess blown off with compressed air keeps everything working just fine. I do usually put a dab of grease on frame rails where the slide moves and often a dot of specialized trigger lube but never been an acolyte of the religion of ritualized stripping down to the last component.

ratbldr427 · Dec 4, 2022

The owner of the Chevy dealership I use to work at managed to shoot himself in the head with a 1911. He and the service manager and their kids were at a shooting range and he went to the car to get more ammo when it happened.
I don't think it was a suicide but maybe he jammed a clip in with a firm grip and finger on the trigger and a live round in pushing the gun up to his head?

Don't know his mental state, but at the time he was one of the most successful dealers in ne Fl. Had plans to build one of the largest dealerships around here.

DanielG · Dec 4, 2022

There is some pistol, don't recall which one, which could fire when dropped even with the safety on. The firing pin had enough mass that, if the angle was exactly wrong, the inertia of the pin was enough to set off the primer.

michiganbuck · Dec 4, 2022

My dad a gun trader found a number of used guns that would discharge by racking through shells with hands/fingers off the trigger. Yes some oddballs he did not have shells for so did not test them.
Some guns had a way too easy-to-off safety, some we would fix and some went to the gunsmith.

He checked every/most fresh gun with the two loads racked through test. Fails he would wholesale to a gunsmith friend who would fix or scrap the gun.

awander · Dec 4, 2022

Doug H said:
While I have never seen the inside of a Sig 320, I do know enough about it to know that it can not fire spontaneously. One of the design elements that make striker fired handguns inherently safe, is that they are similar in function to a double action revolver. The act of pulling the trigger is what "cocks the hammer". In a literal, mechanical sense, that isn't a perfect parallel, in function, it isn't far off.

Different striker-fired pistols work differently. Traditional ones (before Glock) have the striker spring completely compressed, and all that is required to fire the gun is to have something go wrong with the interface between the striker and whatever serves as the sear.

You are correct that the Glock design sits at rest with the striker only about halfway "pre-cocked", and so it is much less likely (though, I would argue, not impossible) for a round to be ignited if the striker should somehow get free.

From what I understand, the SIG design "pre-cocks" the striker to a much greater degree than the Glock does, meaning it is more likely to fire a round if something goes wrong in the mechanism.

Doug H · Dec 4, 2022

DanielG said:
There is some pistol, don't recall which one, which could fire when dropped even with the safety on. The firing pin had enough mass that, if the angle was exactly wrong, the inertia of the pin was enough to set off the primer.

Early Series 70 1911 can do that, but it is rare, and for it to happen the barrel has to be pointed almost directly at the ground, so if you get hit with anything, it will be a ricochet. probably more likely to get hit in the shin with the firearm. most newer 1911's have a lightened firing pin, as well as a stronger firing pin spring.

trevj · Dec 4, 2022

Just gonna say, since we keep rounding off sharp corners, and padding the parts that would otherwise convince the 'dummies' to leave stuff alone, we seem to have evolved a lot more and better dummies out there.

I would suggest that, despite the best efforts of many to 'dummy-proof' things, a better dummy, is always a probability!

As I see it, there will always be that 'one' that comes along, that can break an anvil with a rubber hammer. What we are really short on, is Judges and Juries, willing to understand that despite the best efforts to counter such, there will always be some that manage to find a way past the dummy proof stuff, and that those do not represent the Normal person!

john.k · Dec 5, 2022

As Sir Charles Ross of Ross Rifle fame said.....No gun is foolproof ,therefore fools should not have them.

michiganbuck · Dec 5, 2022

I tell kids that a gun has a desire to just go off, so never let it point one to something that should not be shot.

Cole2534 · Dec 5, 2022

michiganbuck said:
I tell kids that a gun has a desire to just go off, so never let it point one to something that should not be shot.

Please don't perpetuate that stupid shit. It's a disservice to gun owners and it's confusing, it's also flat out wrong.

EVERYONE needs to understand gun safety as part of American life, just as they need to understand automobile or electrical safety. Approach it properly and accurately; leave the fairytale nonsense for the holidays.

Is it mechanically possible for a Sig Sauer P320 to discharge without the trigger being pulled?

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