Today while working up loads for my scoped series 582 RR I had trouble getting a decent sight picture once the barrel heated up. I noticed that groups from a hot barrel only opened up about 1/2" going from 1.5" to 2"@100yds. There was no wind so the heat waves caused dancing of the target & crosshairs which made it difficult to get a good sight picture. I suspect some of my groups would have been tighter without the distortions. I would blow air to sweep the waves away between shots but that interrupted my cheek weld. Would a non ventilated handguard stop it? Does anyone make one?