[Suicide Junkie]

The formulae are pretty straight forward.
The game just plugs in the values for [%Range%] and [%Level%], and out comes the number.
The range at which the weapon does zero damage is its maximum range.

So if you said a formula of := 35
The weapon would do 35 damge period, independent of range or tech level. (Although there is a hardcoded limit of range 500)

:= 35 - [%Range%]
would make a weapon which does 35 at range zero, and fades linearly to nothing at range 35.

More common is to use the iif(condition, true, false) structure.
:= iif ([%Range%] < 80, 100, 0)
So the weapon deals 100 damage out to range 80, then drops to zero beyond that.

Nest your iifs, use square roots, whatever you like.