Any ideas.

[Freak2600]

Seems like lead hole is large to be a sinker. Is kinda ridges around the outside middle.

 

[Tony in SC]

Seal from a lead head roofing nail?

 

[CRUSADER]

I think its tough to ID homemade pieces from lead, they are so numerous, & the personal reasons someone produced it are hard to guess, but it might have been to seal a gap in something.

 

[Al D]

It looks like a lead gasket, used to seal gas line connections