Icewing wrote:
"I found a piece very similar to that among some civil war bullets but never figured out what it is or if it was even related to the war at all."
Icewing, the very similar object you found among some civil war bullets very probably was the brass length-adjustment hook from a musket sling. A civil war musket sling-hook has two holes in the long end, for riveting it to the leather or cloth sling. Something else similar, but somewhat larger than a sling-hook, is a swordbelt-adjuster hook... which has three attachment-holes in the long end. See the photos below.
However, Tlh325's find is definitely not a musket sling-hook nor a swordbelt-ajuster hook... because it doesn't have any attachment-holes in the long end.