... I thought this was a bug in the static.ini :
[Flak18_37mm]
Description German antiaircraft gun Flak 18, 37mm
Icon antiaircraft
// Models
MeshSummer 3do/Artillery/Germany/Flak18_37mm/Live.him
MeshSummerDamage 3do/Artillery/Germany/Flak18_37mm/Dead.sim
MeshWinter 3do/Artillery/Germany/Flak18_37mm_W/Live.him
MeshWinterDamage 3do/Artillery/Germany/Flak18_37mm_W/Dead.sim
MeshDesert 3do/Artillery/Germany/Flak18_37mm_S/Live.him
MeshDesertDamage 3do/Artillery/Germany/Flak18_37mm_S/Dead.sim
// Panzer
PanzerType Artillery
PanzerSubtype 1
PanzerBodyFront 0.010
// Weapon
Gun
MachineGunBoforsUS40AttackMaxDistance 3276.0
AttackMaxRadius 3276.0
AttackMaxHeight 2386.0
HeadYawHalfRange 180.0
GunMinPitch -10.0
GunStdPitch 45.0
GunMaxPitch +80.0
HeadMaxYawSpeed 52.0
GunMaxPitchSpeed 48.0
DelayAfterShoot 1.0
ChainfireTime 4.0
... but it isn't ...!! ???
If you replace MachineGunBoforsUS40 by MachineGunFlak18_37mm then your AA guns won't show ...
Don't ask me why, only Wingflyer knows (may be ...)