How about a few 12 pound cannons?
Or Confederate Williams Repeating Cannons for kids like this reproduction I ran into last weekend?
http://footage.shutterstock.com/clip-2997727-stock-footage-civil-war-williams-cannon-sitting-alone-in-a-field.html
http://footage.shutterstock.com/clip-2997733-stock-footage-civil-war-williams-cannon-top-view-tilt-down-and-up.html