Unintentional discharge (firearms)

Unintentional discharge is the event of a firearm discharging (firing) at a time not intended by the user. An unintended discharge may be produced by an incompatibility between firearm design and usage, such as the phenomenon of cooking off a round in a closed bolt machine gun, a mechanical malfunction as in the case of slamfire in an automatic weapon, user induced due to training issues or negligence, or a simple accident.

Accidental discharge

An accidental discharge (AD) may occur when the trigger of the firearm is deliberately pulled for a purpose other than shooting—dry-fire practice, demonstration, or function testing—but ammunition is unintentionally left in the chamber. Unintentionally leaving a firearm loaded is more likely to occur when the individual handling the gun is poorly trained, and perhaps also with removable-magazine-fed firearms (as the magazine may be removed, giving an unloaded appearance even when a round remains chambered—see discussion of magazine-safeties below).