bull,
I believe the military brass is heavier, thicker walled than commercial brass. The result is it will hold less powder than commercial. Also, check to see if they are Berdan or Boxer primed. If you can de-prime them check to see if the flash hole is centered as in Boxer, in the primer pocket, or two, non-centered flash holes as in Berdan. Also, the Boxer method has the prime anvil as a small component of the primer while the Berdan method has the anvil as part of the case. Acquiring both does mean you must weed out the milsurps from commercial.
Jim