Sig P320 un-commanded discharges

[74novaman]

This is a well documented and witnessed incident that indicates the 320's issues have not been resolved.

The explanation of a "weak firing pin spring" doesn't make sense - the spring was strong enough to drive the firing pin forward with enough force to fire a round.

It loos to me like there are issues with the firing pin / sear interface and the trigger reset.

I don't think he's being intentionally dishonest in the video, but something that jumps out at me immediately is that he's a larger guy, and in the zoomed in picture showing the hole in his pants and where the knife was, you see some of his t shirt hanging over the belt.

This is something I've witnessed myself multiple times in USPSA/Steel Challenge while shooting or ROing: someone's shirt not being tucked in well enough to make sure the holster is clear. I've had to stop guys from attempting to holster with shirt in the way. Now for larger guys, it becomes a big problem when there's enough shirt free to get stuck between gun and holster, especially in something like steel challenge as you move your arms up to surrender position and your whole shirt rides up.

It's possible the gun is defective. My personal suspicion in this particular case is a little shirt got in the way when he holstered, and while raising his arms for the next string it pulled his shirt up enough to trip the trigger.

There were tons of stories about defective Glocks and "glock leg" when PDs switched over to them. Looking at some of the holster options available for 320s, especially light bearing duty holsters, I see a lot of gap between holster and trigger for stuff to get tangled up in (nature of the beast when it comes to light bearing holsters, unfortunately).

Weirdly, a glock style trigger safety might be just what the 320 needs to prevent the edge of the trigger getting snagged by foreign objects in the holster and causing a discharge. That's still my bet for the source of the issues, though.

[Scott B.]

I had the same thoughts as you on the competition shooter. So you say the gun when off when you were re-holstering? Hmmm, didn't see any zebras out here on the range with us.

As to the various LEO incidents, excluding the already litigated pre 2018 drop issue, nobody ever wants to admit they were finger ****ing their gun.

[ORIGINAL TEX]

I own several, one I sent in for the upgrade and one came with the upgrade. They had an issue with a trigger shoe that was heavy by weight, and if smacked hard enough at the rear of the gun the trigger and trigger bar would move backward enough to discharge the weapon. They went to a light weight trigger and a modification to the slide, and offered to upgrade any that were already purchased. However, more could have been done in my opinion. Did all of the 320s involved have the upgrade?

What is not clear in these incidences is whether the trigger and trigger bar are somehow being moved, or is the striker shoe slipping off the sear. Is the sear not fully resetting, after initially charging up the gun and grabbing only a tiny bit of the striker shoe and then working loose from daily activities?

One of the issues I have seen with my 320s if I fully disassemble them is that it is damn near impossible to reassemble it with damaging the trigger return spring and causing a light trigger return. If weak enough I would think the sear may not fully reset and grab enough of the trigger shoe. Unlike a Glock and like the Springfield XD/XDM models, the striker is fully compressed (cocked) in the Sig 320 series. I always have to take a pair of needle nose pliers and re-bend the trigger return spring to get satisfactory trigger return pressure after reassembly. My thought is that this trigger return spring may be part of the issue, and certainly Sig could have done a better job in that area. There are also stronger trigger return springs on the market.

I don’t own a 320 version with a thumb safety like the military models so I don’t know if it blocks the trigger, blocks the striker, or if not fully reset, would the thumb safety refuse to move into the safe position? Perhaps someone here knows the answer to that.

In my opinion Sig could have included a grip safety that blocks the striker and that may help, as would a trigger safety like a Glock, but if the fully compressed striker is slipping off the sear because the trigger is not fully reset, I am not sure it would solve the problem – if that were the problem.

I know some people hate grip safeties, but I have owned many guns with them and they have never been an issue – and are very useful when holstering

[Scott B.]

One of the issues I have seen with my 320s if I fully disassemble them is that it is damn near impossible to reassemble it with damaging the trigger return spring and causing a light trigger return...I always have to take a pair of needle nose pliers and re-bend the trigger return spring to get satisfactory trigger return pressure after reassembly.

Yikes! Don't do that (re-bend). You don't need any tools to take that spring off, or reinstall. Sig's, one day, 320 armorer's class is held multiple times a year here in Texas. Worth your time:

https://www.sigsaueracademy.com/course/ ... tification

[ORIGINAL TEX]

Getting the spring off is not the issue. Getting it back on is the issue. With the new FCU (gold trigger) I don’t see how it can be put back on unless you have three hands.

[Scott B.]

Try it either of these ways.

The current book way to do it is as follows: Take trigger bar in hand, unattached to FCU, and connect the end of the spring. Now attached the hook end to the frame and rotate the trigger bar into position. Attached trigger and proceed on. I'm not sure anybody actually does it this way.

I do it the old way, and have done hundreds of times. It's the inverse of the removal instruction which is as follows: Turn the FCU upside down, with the trigger bar side facing away, rotate the spring away from you to the horizontal position. Gently push spring back toward your body and remove hook from the frame.

To reinstall I just do that in reverse, attach to the trigger bar and slip the hook back into the frame while the spring is horizontal. Can be done without any tools (which is how they used to teach it) but after a few hundred times I use a small needle nose pliers to assist the hook into position but use zero force to do so.