That's not a gun - It's a cannon.
Technically wagga, a "rifled field gun". Just doesn't carry concealed real well.
And Kevin, it's a National Battlefield Park and historic site - US Gov, not state operated. People visit wanting to see Civil War stuff - particularly the way-out-of-proportion number of Asian tourists the park sees regularly. I've never quite figured that one out, but it's a norm for this park as well as the much, much larger Chickamauga National Battlefield Park in northern Georgia. Something about the Civil War touches the Japanese especially, and they flock to certain historic sites and battlefields in the South when they visit. As a hotel GM in Atlanta, I wish I had a nickel for every time I've had to explain that Tara is fictitous and, no, you can't tour it.
That field gun is part of a 4-gun battery on one mountaintop, while another adjacent mountain has a 5-gun battery. All told, probably 20 or so in the park boundaries - a drop in the bucket compared to Gettysburg (which is by far the coolest National Battlefield Park in the US - strongly recommended - you'll get an incredibly deep sense of what Steve means by "everyone losing").