After looking at the cursed thing for about five minutes, I do know it was not used as a roller in any way.
The weight would have left a band around both balls and that is not there. The area between the balls is such that a rod would bend quite easily if any hard mechanical leverage was applied. Has this item been posted on any other sites?
Am I mistaken to assume there is a coat of black paint on the balls or is that just the light the photograph was taken in?
I keep coming back to military use, but I need a size reference on standard armament of this type..(I could come up with something similar in my old wards catalogue....but I will refrain.)