This one really has me stumped. I've been loading 4.2gr of Bullseye in my 9mm rounds using a Lee Classic Turret press and the Pro Auto Disk powder measure. The .49 disk consistently drops 4.2gr, once in a while dropping 4.3gr, but not often. So far I've probably loaded 1200 rounds without a problem. All of a sudden tonight in the middle of a reloading session, it started dropping 3.9-4.0gr and then after about fifteen of those, it started dropping 3.6gr consistently, not 3.7 or 3.8, but 3.6 every single time. I took everything apart and cleaned it, then tried the .53 disk. It was also consistently dropping loads about 1.3gr lighter than usual. Everything appears to line up correctly so right now, I'm at a standstill. If anyone can shed some light on this, I would greatly appreciate it. Thanks.