Index: features.admin.inc
===================================================================
--- features.admin.inc	(revision 7880)
+++ features.admin.inc	(working copy)
@@ -214,7 +214,7 @@
     }
     $tar = features_tar_create($tar);
 
-    $header = function_exists('gzencode') ? 'Content-type: application/x-gzip' : 'Content-type: application/x-tar';
+    $header = function_exists('gzencode') ? 'Content-type: application/x-tar-gz' : 'Content-type: application/x-tar';
     $filename = !empty($filename) ? $filename : $module_name;
     $filename = function_exists('gzencode') ? "{$filename}.tgz" : "{$filename}.tar";