I think the range effect modifier is suitable for some types of units (tanks, AT, infantry, engineers, recon), at current values 1.5.
But for other types of units, that value punished too, making them ineffective units above four hex.
I propose create a new range effect modifier fire, lower, around 1.2, for those units that make support fire for ground combat.
These units could be MG, artillery units with ONLY direct fire, ( infantry guns, howitzers self-propelleded), AA and HAA
Machinegun unit has 2 extra points in soft values on a regular infantry unit. It is very little. The advantage is its longer range, +2 hex, but that advantage is annulledt by current range modifiers, at 5-6 hex, the result is almost null.
The same it applies to other support weapons, 2cm Flak 38 can make an effective defensive fire at 1-2 km, but in the game, at that distance, has no value.