Hi,
I am certainly no Mod expert (not even remotely!
)
But, I would think one way would be to import a sound byte from another game and just overwrite or create the file to coincide with loading of the deck gun.
I am sure someone will come back with a much better answer, but that's what I would try.
One sound byte you might want to try is from "Panzer Commander". It had some great sounds for the shells falling to the metal floor in the tank and then the reload and clanging sound of the breech being closed etc.
Dale