When I do pellet or slug sorting I do both weight and head size. If just wanting to do one or the other I would choose head size as being most important. Kenny
Weight helps cause a i see a 8.5g hit lower then a 7.9 at a given range ..
Thing is if the pellets are same grain tin and your nit picking .0+/- grain i think your hold shows more then the .0 will overall.
Just to add a under is more gurren-teed flyer then one thats slightly tight. In my stuff. But once you find your guns head size and stick to it your consistency is better..