A read tunnel device is disclosed for scanning a plurality of cartons of high density packaged items moving through an enclosure via a conveyor belt. The read tunnel device is positioned over a section of the conveyor belt, such that the plurality of cartons on the conveyor belt pass directly through the read tunnel device. Further, the cartons are induced to tumble as they transit through the read tunnel device in one or more dimensions, the tumbling changes arrangement of the items within the cartons and also changes read direction with respect to the antenna in the enclosure. For example, the read tunnel device can comprise a tube angled down from the conveyor belt so a carton will transit down the tube using the force of gravity. Or, a mechanical structure such as mechanical flippers can pick up the carton and rotate it in controlled increments.