When I was a youngster I used to shoot WW I 303 British ammo that was loaded with cordite powder. Opened at few up as kids and it was all long strands. Apparently they loaded it as they were making the brass and necking it down. A couple of years ago I read somewhere it can break down over time (nitro) and people have been killed by it detonating and blowing their gun apart. Not sure if that is true. I sure fired a lot of it as a kid some 35 years ago.