Using the hornady scale that came with my press. Not sure If I totally trust it. I tare it everytime I measure a load just to play it safe. When I pick the tray up and set it back down it will change by a grain sometimes 2. If I tap it or move it around I will see it change also by 1 or 2 gr. I'm still way under my max load but I would like to be dead on all the time .