A problem is that with time, bumps and bangs, etc. the container will distort and develop a pinhole leak somewhere, compromising the waterproofness of any container. I would shrink wrap the interior contents or at least those that had to be dry in order to start a fire. Perhaps a Tupperware or Rubbermaid container with a good snap tight lid might work as well, although they are bulky compared to a good metal container.