Most bullet cases are made out of brass. I'm no rocket scientist, but brass cases would make a horrible rocket engine material. The only reason cases don't cat

Most bullet cases are made out of brass. I'm no rocket scientist, but brass cases would make a horrible rocket engine material. The only reason cases don't catastrophically fail when you fire a gun is because of the bolt/chamber providing support. Brass IS pretty good about stretching quite a bit before a catastrophic failure. This property is what allows case fire-forming (http://en.wikipedia.org/wiki/Fire_forming http://en.wikipedia.org/wiki/Fire_forming). It's also a pretty awesome safety feature. Cases are so bad by themselves about containing the force of expanding gas, that ammunition fires aren't nearly as dangerous as you might expect them to be. (https://www.youtube.com/watch?v=3SlOXowwC4c https://www.youtube.com/watch?v=3SlOXowwC4c) It's a long video, but if I recall correctly, it demonstrates that a rifle cartridge fired without a chamber doesn't have the energy to penetrate cardboard at like an 11 inch range.