Also, am I reading it right when I think:

Dirty rounds = Post-fall ammunition plagued by duds, hang fires, imperfections and manufacturing errors.
High grade rounds = Pre-fall rounds subjected to higher degrees of quality control.

Or are High grade rounds specifically match grade? Additionally would AET/glaser rounds fall into this category.

Same note, would Heavy Ammunition strictly be explosives ordinance like grenades or would that cover HEI rounds for smaller firearms as well?