I'd seen that page before, and the incident as described does not make sense if the pistol was in proper condition.
The firing pin should not have been in contact with the primer when hammer was down. If the firing pin was way too long it would make contact but not otherwise.
Federal has had numerous recalls of ammunition due to defective primers, some due to primers that were far too soft. They once had a very serious situation with soft primers of a lot of .30-30 ammo.
I have heard of a federal .30-30 cartridge igniting when dropped base down in gravel.
The speculation of a phantom half cock situation might be the answer, in which case it was user error and the hammer was not truly down.
Some liked to carry a exposed hammer auto on halfcock, because that made the cocking motion shorter and easier. I even tried that years ago , but figured it was too likely to break the half cock notch if dropped or if one tried hard to pull the trigger while half cocked. Also in half cock as in cocked and locked theres more pin travel and more inertia imparted to the pin if dropped muzzle down.
As in most situations if something doesn't fit, don't try to force it.