diff --git a/addon/mixins/draggable-column.js b/addon/mixins/draggable-column.js
index 43716872..b464a91a 100644
--- a/addon/mixins/draggable-column.js
+++ b/addon/mixins/draggable-column.js
@@ -125,8 +125,7 @@ export default Mixin.create({
       let table = this.get('table');
       let columns = this.get('dragColumnGroup');
 
-      let _columns = columns.toArray();
-      let targetColumnIdx = _columns.indexOf(targetColumn);
+      let targetColumnIdx = columns.indexOf(targetColumn);
 
       e.dataTransfer.dropEffect = 'move';
       e.preventDefault();
@@ -134,9 +133,8 @@ export default Mixin.create({
 
       table.propertyWillChange('columns');
 
-      _columns.removeObject(sourceColumn);
-      _columns.insertAt(targetColumnIdx, sourceColumn);
-      columns.setObjects(_columns);
+      columns.removeObject(sourceColumn);
+      columns.insertAt(targetColumnIdx, sourceColumn);
 
       table.propertyDidChange('columns');