RCBS and it can vary about 1 gr per throw with flake powder, ball powder is better. I was told the larger difference is when you are loading a small amout of powder such a 5gr load off by 1 gr is a lot, 30gr load off by 1 gr not so much and it makes sence. Since I only reload 45 acp right now, I alway check each flake powder load (red dot). W231 and Bullseye are much more accurate metering wise.
The flake powder does hang up the measure from time to time and when it comes out, it's always way off.