Based upon the P10 design, I cannot explain how a P10 would fire "uncommanded." In my opinion, there would have to be broken parts AND something beyond my understanding would have to happen. A coat string in the holster is another matter.
I am a senior LEO in a command position and I have seen all manners of firearms related issues on both military and LE ranges. During my career, I've conducted forensic weapon examinations and testified to same in court or as part of IA investigations. My testimony has helped put murderers in prison AND my investigations have seen a few of officers disciplined for negligence. Thankfully I haven't had to deal with firearms related LEO criminal misconduct within my organization.
I have seen weapons malfunction. I've seen weapons go off out-of-battery and blow apart. I've seen rifles and pistols slam fire. I've seen coat drawstrings, shirttails and all manner of things get get hung up in in trigger guards/holsters. I've seen cops and military members do some really stupid stuff. All of these issues had causes that could be explained.
A missing spring in a AR hammer will cause the hammer pin to walk and the gun will slam fire upon loading. Bad ammo, fouled chambers can lead to KB's. Weak springs, worn parts, even a primer stirrup can render a weapon inoperable. These are hardware issues.
Poor weapon handling, drawstrings in your holster, failing to put the cam pin in an AR bolt carrier..... etc, are software issues. In 28 years, I have seen many more software issues. I'm also not personally immune from software issues.
I'm not in the habit of badmouthing designs, but someone alluded to the "uncommanded fire" reports with the P320's. In 2015, I led a team to evaluate the 1st Gen P320 as a potential duty weapon. Aside from magazine issues, that design did not incorporate a disconnector (mechanism that would prevent out of battery sear release). Because the 1st gen triggers basically reset on their own without slide actuation, it was possible to hold the trigger in a manner to facilitate sear override that would either result in a dead striker (with a slight primer indention) or the weapon would slam fire. We didn't get around to dropping it before we reported our findings to Sig and moved on to a different weapon. Unlike the P10, the P320's striker is 100% cocked and the sear interfaces very similar to the way a bolt action rifle does. Compared to a Glock or P10, the sear surface is pretty small with a very small amount of metal of the sear interfacing with a small surface on the striker. Because of this design, the success of the system is highly dependent upon the tolerance between the slide and the slide rails. Pull the trigger on one that has seen a 1000 or so rounds and you can watch the slide move up when the trigger is pressed. Add the fact that there is no trigger safety, a very light trigger and a very short distance the trigger must be depressed before the striker safety is disengaged - essentially the weapon is like carrying around a cocked P226 with all of the slack taken out of the trigger. I can understand how a 1st Generation P320 can go off in a holster, particularly with rough handling. With the 2nd Gen ones, with the secondary sear surface and the disconnectior issue resolved, its harder to explain related to the hardware. Because of the lack of trigger safety and my analogy to a cocked P226, I COMPLETELY understand ND's with it. The weapon has absolutely no margin for error.
I don't like Glocks, but I cannot understate the effectiveness of the design. I mention Glocks because anyone doing research can readily find computer animations that clearly show how all of the parts work together. The sear cruciform is basically locked in the frame channel until the trigger safety is disabled. The striker is cocked around 60% with trigger movement doing the rest and sear engagement is pretty robust. Sear reset is automatic. I'm not sure the weapon CAN fire unless the trigger is pulled. If the striker shoe or cruciform breaks off, there is a striker safety, PLUS the striker is under limited tension. If either of these breaks, it is immediately apparent upon inspection. Yes, in the early 90's Glock had a recall because of faulty fire-control components. They could go off upon loading. Different animal a long time ago....
While the P10 looks completely different inside, the parts work together to do the same things as the Glock. The trigger bar/sear is blocked in place by a frame pin until the trigger safety is disengaged. The striker is not fully cocked and there is a striker safety. The disconnector automatically resets the trigger bar. If the striker shoe or sear surface breaks off, I can see the striker releasing, but like the Glock, its only partially cocked and the remaining safety should intercept. The weapon will be disabled, but it shouldn't fire. If it did, the cause would be readily apparent upon inspection. Broken striker shoe...Rounded or broken sear (assuming the striker safety is disabled).
As an examiner, I have had to describe the functioning of the weapon, how the parts work together and whether or not they are functioning normally. Yes, I'm a CZ fanboy but I did ALOT of research before buying a P10. I wanted a Glock that didn't feel like a Glock. While I still prefer the 75 actions, like the Glocks, I cannot understate the effectiveness of the P10 design. I did see a fellow "demonstrate" on the internet how a P10's striker safety is "deficient" but his trick only works if you manually pull the striker past where it normally rides and release it with the slide off. Again, some parts would have to break for this safety to HAVE to work. On the other hand, I haven't actually experimented to see how far you'd have to tension the striker and actually try to set off a primed case with the slide off...can't think of a reason.
Absent of some definitive evidence leading to a hardware failure...can't explain. Sorry.
