Generally no, they don’t just go off. That is extremely dangerous. The Sig P320 has a reputation for accidental discharges and Sig’s reputation has been damaged quite a bit because of it (Sig’s handling of the situation has also been less than ideal).
That said, there are two types of safeties on guns, those that completely prevent the gun from being fired and those that don’t. Both are designed to prevent accidental discharges, but the design philosophy is different for each.
Both types prevent accidental discharge from dropping the weapon (or at least they are supposed to… cough looking at you Sig cough). The difference is that if you intend to fire the weapon, you have to disable the safety on the first type, and don’t have to on the second type.
The news article says that the gun was a Glock pistol. They did not say what model, but Glocks generally fall in the second category. If you drop the pistol or mishandle it, it won’t accidentally fire. But if you pull the trigger, it will fire. The pistol can’t tell the difference between you intentionally pulling the trigger or accidentally pulling the trigger.
Some people consider this type of safety to be less safe, but it’s not unique to Glock pistols. Most revolvers for example have what is called a “safety bar” inside. The bar blocks the hammer from striking the firing pin, so if you drop the revolver or accidentally catch the hammer on something and pull it halfway back and release it, the revolver won’t fire. It’s only when you pull the trigger that the safety bar gets moved out of the way and the hammer can strike the firing pin and fire the weapon. There are plenty of other safety designs as well, such as grip safeties, trigger safeties, etc.
So it’s entirely possible that the gun “just went off” because the guy accidentally pulled the trigger.
It’s also possible that the gun had some sort of mechanical problem that prevented the safeties from working properly. In that case, the gun could just go off.
There are four basic rules for gun safety. They are:
- Treat all guns as if they are loaded, even if you know they aren’t.
- Never point the muzzle at anything you don’t want to destroy.
- Keep your finger off the trigger until you are ready to shoot.
- Know your target and what is beyond it (i.e. don’t shoot a gun at someone on a crowded street because you’ll hit someone behind them)
Every gun owner should have all four of these memorized and should practice them religiously.
If you take this guy at his word, he still broke rule 2. Even if the gun had malfunctioned and accidentally discharged, if all four rules had been followed, no one would have been hurt.
I’m not sure I believe him though.