> I don't think you grasp why so much weight is in the casing... which is to produce shrapnel.
First, what in the world would make you think I don't know why I build my casings the way I do? Second, you are mistaken about the reason. With a low explosive such as black powder, flash, etc casing thickness is all about the pressure developed. Unconfined, these explosives don't so much as explode as burn quickly. The explosion comes from what's essentially a pressure vessel explosion. The burning composition produces a lot of gas very quickly, which creates a lot of pressure. Eventually it blows like a balloon that's been inflated too far. A weak casing will rupture exactly like a balloon - weakly. A strong casing won't rupture until there is a very high pressure, creating a powerful explosion.
A casing that's TOO strong will waste weight, peel open instead of fracturing, and some point not rupture at all.
Next time you think about correcting you might first ask yourself "do I have a clue what I'm talking about?" When you're considering educating someone about what they do, maybe ask yourself "have I ever even once *tried* doing this? Do I really know better than the people who do this stuff?"