UPDATE (31.07.2007)
This is the final view of the Gun:
Here's the interior (with a Crewman for size comparison)
Gun and roof mounted:
UPDATE (02. Aug)
You can see the extra little sight I added right by the engine ventilation.
The rear ramp opened.
And in firing position.
UPDATE (03. Aug)
Added the Rivets and Vision Blocks (Periscopes).