Someone just gave this to me about two weeks ago. None of us knew what it was, but it was military, and he knew I liked that sort of thing, so he gave it to me. After hours of searching by myself, and days of debates among members of the International Ammunition Collectors Association, it was determined that it is an M339 Armor Piercing-Tracer shell, fired by the M4A1/M4A2 76mm Sherman tanks in WWII. It's a solid hunk of steel, don't worry, no kaboom.
@Lindenmeier-Man
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