I recently bought a SIG P320, and a week later, I started reading articles about it self discharging. =P It’s not like it happens all the time, but it seems that if the safety lever spring’s thickness is off by a thousandth of an inch, and the height of the post it fits on is also off by a thousandth of an inch, and you drop the pistol at just the right angle with enough force, the FBI reportedly got it to discharge…
A thousandth of an inch would do it? They couldn't give more margin-of-safety to a critical part like that? A thousand of an inch isn't such a theoretical number. It's about 25 microns, and I've shimmed one of my back-focusing photography lenses for less than that much (about 10 microns, to be specific). This is something that they ought to be able to machine for, but depending on the context, it might not leave much…
If it's true, that's truly terrible design.