Take a look at the Lee Perfect Powder Measure.
It gets no respect, because it's plastic and it only costs about $25. I ran some tests on it a few years ago, and with ball powder the standard deviation of the random error is around .04 grains. With 4831SC, it's around .1 grain. I didn't do any tests with the old long cut 4831.
It beat out the Hornady powder measure and the Lyman digital scale for repeatability. It's a surprisingly good little powder measure.
I can second this. I bought one of these for pistol cartridges so I didn't have to change out the spindle thing on my RCBS and its does better in my hands accuracy wise than the RCBS.
One thing with my lee is it doesn't like some of those flat disk powders. I will admit it does feel like plastic crap but it works.
In the end for rifle cartridges where I load in some volume (batches of 50-250 say). I use a ball powder, I get better uniformity just throwing charges.
