I was not sure if I should post this here on in rifle/shotgun sub forum.
Anyhow this is a declassified Defense Intelligence Agency PDF document that has the common markings of cartridge, can and case, for pretty much all countries of origin. Very handy for identifying that spam can or crate of military surplus ammo.
Maybe made a sticky, not sure how valuable this would be for our members.
Note - this is a 10mb download file.