I'm (still) having a hard time with 'vibration' loosening the sear interface w/ the striker.
If anything -- given spring pressure rotating the sear upwards into the striker tail -- 'vibration' would seem to further impede striker release.
Just to be clear, I'm not arguing one way or the other, just pointing out the contents of the official complaint filed on Abraham's behalf.
If you look through the document I linked, it includes the section of the SIG owner's manual that contained the warning about vibration. It's on page 9 of the document. I checked the current P320 owner's manual and although there is a similar warning in it, it no longer contains the word 'vibration'.
Is a ready to go Sig 320 perpetually on full cock?
Or does the trigger have to move to compress the spring enough to energize the striker?
Here's a video on the operation of the SIG P320.
In this video I explore what it takes to disengage the striker safety on the P320 pistol under normal operating conditions. I will provide viewers with an in...
www.youtube.com
The SIG P320 trigger does very little in the way of tensioning the striker spring, as far as I can tell. It releases the striker that is cocked by the action of the slide. But the design does have a firing pin safety to prevent the striker from hitting the primer if the sear somehow drops it.
Below is some discussion about the SIG P320 design--I'm not claiming this is what happened in the Abrahams case. This is just me talking, in general, about the design and speculating a bit.
As I mentioned in a previous thread, the firing pin safety is kind of interesting in that the trigger disables it pretty early in the trigger pull--after less than a tenth of an inch of travel. There is no tabbed trigger safety which means theoretically, a badly designed holster could tension the trigger by applying pressure to the sides of the trigger. This would have no effect on a gun with a tabbed trigger safety because trying to pull the trigger by applying friction pressure to the sides can't overcome the trigger safety to move the trigger. So let's say that a badly designed holster pushes the SIG P320 trigger back about 0.1" when the gun is holstered. The gun isn't going to fire, because the trigger is only about halfway pulled. The gun could stay like that indefinitely with the sear holding the striker in place.
So, how could the gun fire in that situation? It would require some significant amount of play between the slide and frame. If wear, or poor tolerances, or some other issue allowed significant play between the slide and frame, and something torqued or pulled the slide upwards, it could move it enough to pull the striker and sear out of engagement. The Complaint document lists the comments of a certified SIG armorer characterizing sear engagement as being about 0.25mm--less than a hundredth of an inch. Doesn't take much upward motion to turn 0.25mm from engagement to disengagement. And with a defective/damaged/worn holster tensioning the trigger enough to disable the firing pin safety, if the sear comes out of engagement with the striker, the gun will fire.
I commented in the other thread that one reason I hadn't purchased a P320, in spite of what I consider to be a number of very attractive features, is because I had noticed on the P320s I handled that the slide moves upwards noticeably when the gun is dry-fired. That's something I've not seen in other firearms and it bothered me.
