Detonators
These are what we used to call detonators. Now that I am a grown up malchick I know that they are in fact Hilti cartridges used in Hilti power tools to hammer nails into concrete and so on. In those dark distant days these were, from time to time, to be found on the estate. Someone figured out that they were not bullets – good. And then some other clever fellow figured out that if you placed them on a flat surface and hit them with a hammer that they would explode with an almighty bang, louder than any firework. They also made quite a bang if you popped them into a fire…… Seeing this picture makes me want to go out RIGHT NOW and buy a box of detonators and set them off in my bathroom