Hum... The guy seems to be saying that it was originally developed for a "black powder rifle cartridge (8mm Lebel)."
That's incorrect, the 8mm Lebel was never a black powder cartridge. Other than that, pretty good video.
No the lebel was one of the first smokeless powder cartridge but it was based off of a black powder cartridge. In fact it's just a a necked down 11 mm Gras black powder cartridge. Because of it's odd design it had many problems. It was not a very good round especially for the Chauchat(Sho-Sho). I do like the Lebel rifles though. I keep meaning to pick one up just for historical reasons.