Particularly with the 500 steel. I'm also thinking about a setup for hanging steel with a chain but making the holes in the steel will be a bit much. On the longer targets, maybe just silhouettes set in between railroad ties. Gongs, at longer distances, I haven't even thought of yet. Going out, as soon as I get feeling better, to pick out a new site to shoot that don't have a river running through (and over) it at times. Ha!Repeated hits in large volumes will cause almost any weld to crack. Try to design the plates without welds.
I spend a lot of time every month re-welding steel targets from our range. I'm guessing harmonics from the hits generate the cracks.