I went and removed that from my post, as looking at the Armour School Courses, there was no such beast listed.
The Master Gunner Crse is an all Arms crse that involves a lot of technical calculations, with a difference between what the NCM's must do and what the officers must do. It involves visiting various companies that produce munitions and systems. It is quite a prestigious qualification to attain. Old Sweat may be better to elaborate on what it all entails. It definitely is nothing like the Advance Armour Gunnery Crse.