unknown solid lead looks like a mushroom on both ends. any idea

[johnnyrum]

Found today at a sight I've previously dug civil war bullets at. Solid lead and probably weighs 5 lbs or so. Any ideas what it might be

 

[CRUSADER]

It looks like what I would label as a huge pot mend. We find many on ancient sites, not to say its ancient, just to say its a hole plugger for an unknown pot/object.