I have hung clay pigeons from clothes line type arrangements. You might be able to weld bits of round stock on the metal target face to make a stub to hang them on. I have also seen handgun silhouette targets mounted so they rotated around a foot mount like a swinging target, then were reset by a horizontal bar that lifted up and forward, but the distance was only 200 yards max for the rams. A friend of mine built one with relatively light plates that would swing around like a propeller when struck by a centerfire round. It was mounted in a swing set like arrangement. The plate was welded to a rod. This was welded at the other end to a short piece of round tube stock. A smaller piece of tube passed through the larger tube like a drive shaft or axle. This enabled 360 rotation. It was cheap, simple and easy to make. Hope this helps.