It is heavy steel and it appears to have been machined. It weighs 6.5 pounds and the walls are 3/16″ thick. It appears to have had a leather carrying strap attached at one time. The clasp holding it shut appears old.
I have no clue about this !! I have not seen anything similar !! I don`t know about a leather strap type handle !! I would think a wire bail type handle !!
What about some kind of army kit? What a fun find!