Chimo Sapper!
At first glance it looks like a 25 pounder but it is a captured Italian field gun of Scoda ancestry if I don't miss my guess. Note the horizontal sliding wedge breech block and the arc shaped bits on the top shield flap. The spider type hubs are also an indicator of European vice Albion birth.
I'll grab one of my source books tonight and see if I can get you a better description.
Ubique!
Mike
