You may just have to set a minimum range. Aside from that, you can mess around with the pitch settings and hope something works. You have a decent number of settings to play around with:
TurretTurnRate = [integer]
TurretPitchRate = [integer]
NaturalTurretAngle = [integer, default 0 = horizontal]
NaturalTurretPitch = [integer, default 0 = horizontal]
FirePitch = [integer, default 0 = horizontal]
MinPhysicalPitch = [integer, default 0 = horizontal]
GroundUnitPitch = [integer, default 0 = horizontal]
TurretFireAngleSweep = [weaponslot][integer]
TurretSweepSpeedModifier = [weaponslot real number]
ControlledWeaponSlots = [weaponslots]
AllowsPitch = [Yes/No]
MinIdleScanAngle = [real number]
MaxIdleScanAngle = [real number]
MinIdleScanInterval = [integer, milliseconds]
MaxIdleScanInterval = [integer, milliseconds]
RecenterTime = [integer,milliseconds]
FiresWhileTurning = [Yes/No]
InitiallyDisabled = [Yes/No]
Originally Posted by: Annihilationzh