Here's a homemade adjustable one.
No camera though, so no picture.
Years ago, I wanted something more precise than the usual, so I made one out of a large Lee dipper, a screw and a plastic washer that was a tight fit in the dipper.
Just turn the screw to raise or lower the washer to the amount of powder desired.
It's come in very handy on occasion.
Lock the doors, they're coming in the windows.