were often two-piece construction: a solid base, with the rest of the body made of thin sheet brass wrapped around a mandrel, then the seam soldered closed and this trimmed and soldered to the base(sometimes brass, sometimes cast iron). For instance,
Which gave rise to a common problem, primarily when a lot of shots had to be fired in short order: the barrel, especially in the chamber area, would get hot. Really hot. Enough so that, if you didn't space your shots enough, it could cause the solder to soften, which meant next time you worked the action the extractor could rip the base off. This is Bad, as you couldn't load until you managed to dig the body of the case out of the chamber.
When they figured out how to economically and cost-effectively form cases from solid brass(and later from steel) it ended the problem.
And yes, that's a paper-patched bullet.