Hang fire

Hang fire is a term that refers to a state in which an unexpected delay is encountered between a firearm being triggered and the initiation of the propellant. This mode of failure was common in firearm actions which relied upon open primer pans, because of poor/inconsistent quality powder. Modern weapons are susceptible, particularly where the ammunition has been stored in an environment outside of the design specification. The delay is typically too small to be noticed, but may be disruptive in processes where accurate timing is important - as in synchronization gear in propeller driven aircraft.

A hangfire should be initially suspected whenever a weapon fails to fire, but has not clearly malfunctioned--i.e., the operator believes that the weapon has correctly cycled a fresh round, the weapon fails to fire, and the action is not visibly jammed. The correct procedure in this situation is to keep the weapon pointed at a safe target for thirty seconds, then remove and safely discard the round. In modern, serviceable weapons it is much more likely that a "dud" round has been encountered and the round will never fire at all. Still, it is important not to immediately remove the round from the chamber, because if a hangfire has in fact occurred, a round detonating outside of the weapon could cause serious fragmentation injury.

The term has been adapted as a form of early 20th-Century slang to describe an occurrence of incontinence.

See also

• Squib load