Q From Joy Burrough-Boenisch in The Netherlands: Can you tell me the origin of the expression to hang fire? A friend in the States came across the expression in an article on the Reuters online news service: ‘NATO warplanes were stepping up air strikes on Yugoslavia as peace efforts, which seemed all but successful a few days ago, hung fire’.
A Unlike so many expressions, this one is well understood. It dates from a time when firearms were loaded using a gunpowder charge poured from a flask, which was then ignited by a spark from a flint striking against an iron plate. Gunpowder was notoriously unreliable, partly because it varied a great deal in quality, but also because the slightest damp stopped it igniting properly. When this happened, the powder in the firearm smouldered instead of exploding and was said to hang fire. (This was highly dangerous, as you may imagine, because the remainder of the powder might explode at any time, perhaps while its owner was trying to clean the gun out and reload it.) So to hang fire became an expression for some event that was slow in acting or of a person hesitating, usually with the inference that a matter of some importance was involved.
This expression should not be confused with a closely-related one a flash in the pan, for an ineffective effort or outburst. This referred to gunpowder that burned fiercely but ineffectually in the touch hole of a gun, without igniting the main charge. The result was a flash and some smoke, but the gun didn’t fire, and the ball didn’t actually go anywhere.