Sorry for the delay.
Here's my WEAPONDATA entry for the GR7 gunpod. It still needs a tweek to match the muzle position exactly, but it works.
Also the shell ejection position needs a tweek. Maybe it also needs a left and right gunpod?
[WeaponDataXXX]
TypeName=GR7 gunpod
FullName=GR7 gunpod
ModelName=GR7-gunpod
Mass=200.000000
Diameter=0.500000
Length=3.500000
SubsonicDragCoeff=0.200000
SupersonicDragCoeff=0.770000
AttachmentType=UK
SpecificStationCode=
NationName=RAF
StartYear=1990
EndYear=2020
Availability=2
BaseQuantity=50
Exported=FALSE
ExportStartYear=0
ExportEndYear=0
ExportAvailability=0
WeaponDataType=3
GunTypeName=30MM_ADEN4
MaxRounds=125
MuzzlePosition=-0.084500,2.078100,-0.246300
LightPosition=-0.084500,2.078100,-0.246300
AimDirection=0.000000,1.000000,0.000000
EjectShells=1
EjectPosition=0.212100,0.953200,-0.145400
EjectVelocity=0.000000,0.000000,-2.000000