At Shield, we have sold more than a few Sig Sauer P320's. Most of them have gone to sworn law enforcement officers, as the pistol is not approved for sale to civilians in California. Cops love the pistol. It's accurate, durable, light, and completely modular. Recently, a design flaw was discovered in which the P320 would discharge when dropped in such a manner that the weapon's backstrap and slide contacts a hard surface simultaneously (negative 30 degree angle). Sig Sauer has gone to great lengths to explain that this scenario falls outside of American National Standards Institute (ANSI)/Sporting Arms & Ammunition Institute (SAAMI), National Institute of Justice (NIJ), Department of Justice (DOJ), Massachusetts, California, and other global military and law enforcement protocols.
The mechanics behind the problem:
When dropped in the manner described above, inertia keeps the trigger of the firearm keeps moving to the rear, through it's pre travel pivot, clearing the striker plunger, and subsequently firing the pistol.
Once this problem was discovered, Sig Sauer immediately halted production of it's commercial offerings of the pistol and offered a free upgrade, bringing the firearm to military specifications, and installing the same reduced mass trigger shoe, and striker. This upgrade also replaces the pistol's trigger disconnect safety and sear with one of a changed geometry. Repeated attempts by Sig Sauer or others to duplicate the drop safety failure after these upgrades have been completed have not been successful. (see TTAG embedded video)