Silver Worm
First thank you for your service to our great country, Even if you never seen any UFO's
As for your relics , the buckle could date to the civil war , it's very hard to say for sure as that type was used for many years , 'it likely once had an iron tong, but it may have had a Brass one

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It being a brass frame tells me that it was made for med to heavy use & have seem many similar to yours ( Many variations ) a few bigger or slightly smaller etc .
If the area you dug it has produced a good bit of Civil War Relics I'd display it as a Civil war piece (but would or could say it's 100% Civil War era ).
As for your other round piece , I have found many similar types & IMO Could be off anything so I keep them in my 'Grey To ID / recycle Box' & hopefully someday I can see those such pieces in a Civil War sit-u.
Wish I could help more & Good luck in the future.