One more thing I discovered....If your barrel gets warm (hot) you will start to see mirage. If you shoot through this barrel generated mirage your groups will open up considerably. A small battery fan will get rid of it or a "mirage shield. Mirage shields however don't work to well on spotter bbls.
Unlike mirage generated by the sun you cant hold differently and shoot through barrel mirage.
Barrel mirage will destroy a group even more than those excellent things pointed out by MD
Lefty
