Hi all, went out real quick and found lots of .22 cal ammo, a 1940 wheatie, some whatchamacallit ring thing and what I think is a .44 Henry Rimfire! It's soaking still in hydrogen peroxide to try and see it better.
Thanks all, I posted in what is it also. Single round firing pin wasn't too common for this round. This is why I love metal detecting, get to go home and the hunt continues with the help from you all!