[Doozie]

Originally Posted by Nebit

hand it to the museum, you'll be credited and they'd tell you what it is.
it looks like some type of ammunition anyways.

Well, you'll be credited if they exhibit it. Legally, if its an artefact, you are obliged to hand it in. The museum are very happy identify and advise you otherwise.
well done.

[gravensteen]

Could be lead shot. I've dug up lead shot (from a rifle, usually late 19th, early 20th century rifle, British Army standard issue) and when that hits something hard, it can dent.

[James Bong 79]

7 up bottle cap????