[FC]

FC, what would the two ways be?
The way I was thinking is faulty, it would lead to nonsense if the truck "towing" the gun is destroyed...

One option is to make new vehicle with gun mesh. That object you can use in convoys behind the truck.

Another option is to make vehicle that is made of truck mesh and gun mesh combined. Only drawback of this option is when in turns this vehicle will turn around single pivot point unlike RL where truck and towed gun will pivot around different points.

FC

PS You can use that mod I gave you to test both options. Use tank slots for test purpose.