After looking at this photo – again – I am at a loss as to how the ammo boxes could be fitted to a mount that was located so far forward in the fighting compartment. They certainly would have interfered with the driver. Perhaps we are seeing a Drilling on the other side of the m.SPW altogether? It is entirely possible that it was trailer or cart mounted as a way of mobilizing AA protection for an artillery unit. We apologize for the misconception.