An emailer makes an interesting and valid point in regards to a brief in Sunday's paper about a man who shot and killed his own son. A version of the same story is here.
Please keep in mind guns do not fire themselves. They only fire when sufficient pressure is placed on the trigger mechanism. The exceedingly more accurate terminology used within the firearms community and profession is "a negligent discharge occurred." The bottom line is someone was being negligent in handling the firearm, thereby exerting sufficient pressure on the trigger to cause a discharge of the gun. 'Negligent discharge' puts the blame where it belongs: on the gun handler. "The gun went off" incorrectly puts the blame on an inanimate object that is not capable of making a decision: the gun.
There's no subject where readers pick apart language more carefully than with firearms. I don't necessarily think "to go off" is necessarily inaccurate, especially before an investigation of the incident is completed -- but duly noted.