Dennis - Jack Haddock was the first to mention a possible copper rim #5 and #6 from Sierra Sids, when I got mine they looked to be just a bit different from the regular brass rim, I don't think there are any true copper rims from sids like the ones we saw from the Hilton etc.I think it was just a little more red in the brass. You might email Jack and see what his thinking on the matter is at this time.
Walt