Foating Target

I've been looking for a floating target for my pond. Was thinking about a metal floating ball, one that I could anchor like a buoy that was small - 3 inches or smaller - and would hold up to shooting with a .25 cal at 50 yards. The reasoning for this is to have something that would last longer than a foam float. May not be possible, but if there was a possibility I was sure AGN would be the peeps to ask. Any Suggestions?
 
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​John Eroh (John_in_MA) made this floating base for my clubs Duck field target out of PVC plank no foam at all. He used a telescoping snow rake rod and two guy lines to secure it to the shoreline.