I beg to differ (especially when using smokeless powder in a altoids size or bigger can), it wont kill you on the spot although it will do enough damage to your feet to make you wished it did. Obviously the addition of capacity and shrapnel will add to the effect. Like almost all improvised devices, there are no safety features which makes it as dangerous to assemble as they are when deployed against an adversary. I could think of much more efficient uses of gun powder though...I dont think black powder would be powerful enough to create the explosive charge needed to frag kill. Black powder is low energy...and "burns rapidly" rather than explodes. Modern smokeless powder would likely produce better results.
....IT worked well 20 years ago when i first tested it,infact 3 for 3, saw it on some raw footage out of bosnia...guess it all depends on your "actual" skill level...Doomsday preppers was a joke, and an insult to real survivalists,weather or not those guys were idiots is beside my point, they were portrayed as such, They did nothing but harm and negative exposure to the movement...jmho.Saw that on doomsday preppers. It failed like 3 times lol