British model 1842 percussion lock musket, 1842-1853

Caption: British model 1842 percussion lock musket, 1842-1853

The 'percussion lock' was a technology adopted in the early 19th century to replace the earlier 'flint lock'. The lock was the mechanism that set off the gunpowder charge inside the weapon's barrel. Flint locks used a piece of flint scraping along a piece of steel to make sparks. They were strong and easy to make, but not especially reliable, and very vulnerable to damp. The percussion lock used a small copper cap containing fulminate of mercury, which exploded when hit by the lock's hammer. The result was a more reliable spark, but the new mechanism was quite expensive. After experimental trials, the percussion lock was adopted by the British army in 1839. At first, existing flintlock weapons were fitted with percussion locks. In 1842, the pattern of muzzle-loading smoothbore musket shown in this photograph was introduced. It remained the principle British infantry weapon until replaced by the 1853 pattern rifled musket. (Parks Canada)