The large caliber brass case was probably squeezed to remove the
bullet which is tightly crimped to "keep your powder dry" I think so
that the "smokeless" (?) powder removed for some other purpose perhaps
by a "child" perhaps not. However as youngster I did do something
similar with a shell casing from presumably Missouri and rolled the
powder into a paper taper using white glue. When the end was lit in a
small fire it exploded throwing the us three "children" to the ground.
We had thought it might just burn like a fuse.

George Myers