Conversely , steel is more susceptible to contamination and damage so all such cases are varnished or otherwise sealed against the elements .
However , case weight ( mass ) affects how much ammunition a soldier can carry , so the lighter steel cases do have a military advantage .
Steel is more susceptible to contamination and damage so all such cases are varnished or otherwise sealed against the elements .
However , case weight ( mass ) affects how much ammunition a soldier can carry , so the lighter steel cases do have a military advantage .