This is a wee thing thats in Mr Mears book and is a handy way to recycle cartridges and use them for matches or cotton wool and vaseline tinder, they're also handy as wee survival kits containing fish hooks and shot and other small items, very easy to make and handy if you find a load lying around when you're out
You will need 2 used cartridge shells,
Place one in the fire and burn off the plastic casing just leaving the brass cap, cut the other one down until it's the size you want
hoke the cleaned brass cap out of the fire, let it cool then squeeze it over the end of the cut down shell
and finished product, easy peasy lemon squeezy..