It’s amazing how much stuff gets left lying around after war.
A forest was cut down and bulldozed for a development of townhouses across the street from my old office in Fairfax, VA. It was part of the battleground of the Battle of Ox Hill/Chantilly. I found a fired minie ball that had struck something soft, fallen to the ground and looked like it got stepped on. Looking up the battle maps, my friend and I were able to make a pretty good educated guess what northern regiment fired it at which southern unit. A guy with a metal detector came out, and was finding little piles of unfired bullets all clustered together. We figured it was probably where someone took a hit and went down and stuff fell out of their pouches. It was pretty easy to trace where things were happening by locating little finds like that.
Find of the day was a cap regimental(?) number insignia fragment by the metal detector guy.
I was part of the North-South Skirmishers back in the 1960s. We ran into one guy with a detector who told us the same story - along a trench line he'd find those little mounds of unfired bullets, usually no more than five or six. None of us could make any sense.
Then in July 1961 we did the first re-enactment of the Battle of Gettysburg and our postion was up near the High Water Mark. During the hottest part of Pickett's Charge we were firing as fast as we could. In our excitement we pulled out a handful of cartridges and laid them alongside us. At that moment me and my buddy looked at each other and had an "O Sh!t" moment. I'll bet the same thing happened at your place so long ago.