Not much has gone right for copper bulls in the last few months. Mine production continues to grow with little interruption, China’s clearly in slowing mode. Then why did money managers cut their bearish bet on copper futures by 40% in the week ended on Tuesday? Because things could have been worse. After a couple of bearish surprises on China earlier in the year, investors went into this week positioned for the worst. An on-target reading on Chinese GDP was enough to push bears to cash out.