creating a new, fictional oob

[Zocktan]

i've got to "convert" the following posleen weapons to the game:
-a normal shotgun,
-a 1mm railgun, able to pierce the armor of APCs,
-a 3mm railgun, able to pierce the armor of Tanks (even Abrams'),
-high velocity missiles and plasma cannons, ahem, VERY powerful.

the only units the poslen got are platoons (hordes) armed with those weapons.

any suggeestions which weapons from the game could be modified in a way, that they fit as the posleen-stuff?

@thatguy96
THX!