TexasCHLforum.com

esxmarkc wrote:

There's also scenario C:
The firing pin block pin got gunky, the spring that's supposed to reset it wasn't strong enough at first so the gun legitimately slam-fired, but the shock of the gun going off jarred it lose preventing continued slam-firing. (Don't laugh too hard -- the manual specifically tells you to make sure this part is working correctly as part of the cleaning procedure.)

Ok but keep in mind that:

A. It would have had to lock forward on the last firing of the last round shot out of the handgun. Any other round loaded would have either slam fired or shoved the firing pin back into the slide.

esxmarkc wrote:So is it possible that your friend was the big looser in the slam-fire lottery? Given the multitudes of handguns around the state of Texas that are charged every week it is certainly possible even with incredibly steep odds.

But condider this: Most all Sigs are hammer fired as opposed to striker fired (not all, but most models I am familiar with) and, most Sig models have a firing pin block safety system. Boiling this down:

A. You must have the trigger pulled in order for the firing pin to have access to the primer even if the hammer somehow releases foward on it's own the firing pin won't see the back of the primer. Many Sigs have hammer decocking levers as testament to this.

B. If the firing pin were frozen foward of the bock and protruding, the inertia of the slide would have to be sufficient even after stripping a cartridge to provide the force required to fire. AND if this were the case then the weapon would likely have continued to slam fire until it was empty and you could still find the pin in it's forward position.

So my answer is that depending on the model of the Sig I would have to say it is VERY improbable although not impossible, it is VERY, VERY improbable.