Stone tools were still being regularly used in Europe in the 19th century as part of the firing mechanism in flintlock guns. Flintlock guns, as their name suggests, used a piece of a type of stone called flint in their gunlock. The pieces of flint used in these gunlocks are referred to as gunflints (Examples of gunflints) and like prehistoric chipped stone artifacts were fashioned through the percussion or pressure flaking of a preform (This blog has a excellent discussion about the manufacture of gunflints.). Once the gunflints were prepared they were secured to the end of the gunlock's hammer. When the gun's trigger was pulled this hammer sprung forward causing the flint to hit a piece of metal, which generated a spark. This spark in turn ignited the gunpowder, which propelled the bullet from the gun. Here's a good animation that illustrates how flintlock guns work.