Out on range last week shooting federal 160grn rounds at 150m target. Ran out of these so switched to winchester 160grn rounds. My rounds now struck 2'' lower and 2'' to the right. However afterwards I noticed my barrel was hot. So was it the change of bullet brand or was it the hot barrel that affected point of aim so much? I'd fired 10 federal over a couple of mins before switching brands. So off I went yesterday to find out which one was the culprit. Set a 5'' target out at 175m and fired 3 federal rounds first. All on the button. Let the barrel cool whilst went for a walk over to target and back. Switched to winchester and let off another 3 rounds. Again all on the button. So hot barrel to blame for change of point of aim? Something to remember when taking multiple shots in quick succession.