Glocks' extra lever in the trigger prevents the trigger from being pulled back by inertia. Sig's fix is to lighten up the trigger parts by 30% to decrease the inertia. I imagine any trigger that has a lever or some other mechanical block on the trigger itself would not have Sig's issues (Ruger's C9s Pro also has a trigger lever, for example).So are Glocks vulnerable to firing if dropped muzzle-up?
What about Springfield XD pistols?
Or Smith's M&P series?