Half a grain seems like a very big swing,that would be troublesome.
I use three type`s a lee beam, a Lyman DPS, and a frankford arsenal.
The frankford arsenal gets used quite a bit for load work up. The thing when I zero it and remove the pan, it has always reads -73.6 grains since the day I bought it a few or more years ago. It will however drift a little and I can tell when it does this by minding what the negative reading is w/pan removed...I just dump a pan here/there and rezero.
