Gentlemen,  I would appreciate the knowledge of members with more experience than I on this item. 

It appears to be iron, about 4", and has been plugged with what seems to be cement.

It has a single mark that I can find. The mark appears to be  a numeral "1".

bump

I’ve thrown a few shot putts but never saw one with a hole in it filled with cement.

 

Could be where a fuse went?

Thank you. That is what I had originally figured it was, as it came with a good amount of original dug and non-dug civil war stuff. Just wanted to see if there were any knowledgeable folks that could lend their expertise and opinion.