While in Phoenix I was able to shoot some interesting steel targets and they REALLY ring well no matter where hit. Basically all the plates are free floating on a piece of rubber conveyor belt. A section of old tire in the tread area would probably make a good substitute. From my understanding the targets in question have been in use for around 5 years and look to me like they could easily last another 10 more. The pictures are not the greatest and also include the stands so if someone wanted to make a clone they probably can pretty easily though I would likely make a couple changes for my own setup on the stands.