Even packed to the gills, I've never had an issue on any domestic or international flight using it as a carry on. I can recall maybe one or two occasions where

Even packed to the gills, I've never had an issue on any domestic or international flight using it as a carry on. I can recall maybe one or two occasions where no overhead space was available and I needed to remove a few items from the fully loaded ruck to fit it beneath the seat, but those were situations were outliers.