[Mobhack]

if the gun was not an AA gun, it probably would not fire at air targets.

It was probably meant as a bunker for firing at landed troops in the scenario in direct fire mode. (We don't do large calibre AA guns, which were for salvo flak-curtain fire at high level bombers, only those up to about 57mm auto cannon which fire individually at individual plane targets).

Cheers
Andy