Quintessential "War Metal":
Bolt Thrower: Realm of Chaos, Warmaster
Immortal: Pure Holocaust, Battles in the North
Thematically, musically, these four albums are all one needs to construct a complete image of war. Metal can be used to paint a surrealist mental landscape, its regions delineated by potent contributions of outstanding bands alone. Once this is accomplished, we realize that 99% of what is out there is superfluous. Self-professed "war metal" acts are footnotes to the development of metal throughout the 90s.
P.S. As per GreatBlackJoy's comment, Beherit's "Drawing Down the Moon" is about as far from "war metal" as Burzum's "Hvis Lyset Tar Oss", and should be considered more or less analogous to "Electric Doom Synthesis". You would've been closer with another Finnish band, Impaled Nazarene, although even they drew inspiration from esoteric themes up until "Ugra Karma".