Reload Solr core with curl
1.Try to use -A to specify the User-Agent
curl -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" http://localhost:8983/solr/admin/cores?action=RELOAD\&core=mycore
2.Curl can't exec js scripts
So make sure it is not because of the js scripts.
You can use Developer Tools of chrome or Firebug+Firefox to check the http communication process.
3.Use wireshark or sth to check whether "the call is arriving to the Solr server" or not.
I hope that helps.