I use a pump type powder dispenser that feeds directly into a cartridge held under the nozzle and check about every fifth load on a digital scales. The newer, automatic scales that are combined with an automatic dispenser would not be a great help, as they (as yet) do not feed directly into a cartridge. The powder falls into a scoop that then has to be filled into the cartridge, most likely with the help of a funnel. I find that my powder dispenser is quite accurate, but that accuracy changes as then powder level in the container drops.