Here goes...
The piece measures 13" long total, ball diameter 11", bar length alone is 6", and bar is 4 1/2" wide. In my defense, this piece is unmarked, made of forged iron with balls braised to the bar. forging flaws are evident. Patina is chocolate brown. A 2 lb and 4lb cannon ball in pic for comparison. The only thing that didn't come out well in the pics is the roundness of the balls. The pics make them look more ovoid, but in real life they are as round as any of the other artillery shot I have. My argument is that this is what barshot looked like toward the mid/late 19th c. Easier to make than the hand-wrought square barred type of the previous century-

Dumbells were typically marked, cast as one piece, just as often made of steel than iron, and didn't have bars this thick or long.