Today I tried some gongs I made up out of some old steel, about 28mm thick. I thought that the thickness of it would help it to stand up to gunshots, but after shooting at them from 200m with .308 win and 6PPC I found they pock badly. Very badly. If one spot is going to get hit a half dozen times, it would probably bust through. The steel was rusty and had been lying a a yard for years, I got it cheap so that's just as well. Back to the drawing board. I can't find a source for any more suitable steel here in Italy. What are some alternatives; I have heard that man hole covers work well, but they are made from cast iron here. To the best of my limited knowledge, cast would break apart after some shooting, wouldn't it? I am also thinking about cutting up an old dozer blade, that should be pretty hard steel.