Our area has been active since the 1600's. My neighborhood since the early 1800's for sure. Found this cartridge case in a wash out area next to the house that gets run off from the roof during heavy rains. It's a rim-fire case, brass, and just a tad larger than a current day 9mm. Head stamp simply says US. During the Civil War our little town was both Union and Confederate depending on the day. Loads of activity, we even have a yearly reenactment down the block from us. Anyone have an idea of what it actually might be from?