

Some sort of cast iron weight (30lbs), shiny metal upon scratching. Found in my garden under a bush Dorset uk.
Found this buried in a garden in Dorset, UK. It is solid cast iron (confirmed by a metallic scratch beneath the mud crust) and weighs exactly 30 lbs. It measures 3.5cm x 28cm x 20.5cm. It features interlocking grooves on the side profile, a stamped 'B', a stamped 'D', and the Roman numerals 'XXX' (matching the 30 lb weight). One end is cleanly snapped along a pre-molded scoring line. Looking to identify the foundry or original industrial/maritime use!
Thanks
*EDIT 1- might not be cast iron as it’s not magnetic. However Google is saying the dimensions don’t fit the weight. I guess it could be mixed with other things?