Need way more info than a single picture with no history, description, magnetic?
need shot of other side and then some
explain , describe the hole - is there anything in the hole, is it threaded
looks like there's some sort of insert in the hole
need an idea where it came from
What do you mean its from a productive site, what other finds have you found, may give us a date range to better help you ID
If you don't help us out, we clearly cant help you out
BRadyboy