The Uncommon Origins of Some Common Expressions:
A combat scene:
The original flash in the pan occurred in the flintlock gun. This was the old unwieldy kind of musket used before the development of the percussion cap or cartridge. The charge that propelled the bullets, in those early days, was in the form of loose gunpowder, which was carefully measured and placed in the pan or flashpan of the gun, where it was ignited (or, all too often, failed to ignite) by a spark from the flint. If the gunpowder was insufficient, it might fizzle or flash rather than explode effectively.
The three related phrases are to hang fire a damp squib, and lock, stock and barrel.
To hang fire is to delay, to put off one’s decision, to wait and see. Originally, a flintlock gun was said to hang fire if it took a long time for the charge to ignite.
A damp sqib, something that fails to live up to expectations, is, literally, a firecracker through being damp fails to generate the climactic bang.
As for lock, stock and barrel, these are the three main components of a musket or rifle: the barrel out in front, the stock – the heavy wooden handle or support – the mechanism designed to explode the ammunition charge – in the middle. So to buy up a business lock stock and barrel, for instance, has come to mean to buy the whole thing. Or as Australians would say, the whole kit and caboodle.
Acknowledgements: Readers Digest.