I use a Lee Perfect powder measure to load 17 calibres across a range of powders and have always found it to be consistent to within +/- .1gn most of the time.
There have been a few occasions with certain powders, when I have had a `bridged` charge the only threw a reduced load.
I countered this by transferring every charge from the measure into my Redding No.2 beam scale, that I had previously checked with a set of RCBS check weights.
Call me anal if you like, but I know that every powder charge is right on the money every time.
ukrifleman.