Okay so I think I figured out why the Autodrum was so innacurate. I ignored the instructions, and installed it using logic. I seated the measure to a depth which was too deep in the press, and then kept raising the depth, until I could no longer feel plastic making contact with the drop tube. This ensures full rotation of the drum. The depth window is very small. Now it throws consistently within 2 tenths of a grain, which isn't great, but at least I won't see another squibb hopefully. I only use it for pistol, so good enough for me. If I load for rifle or PCC, I'll use the Chargemaster light.
Thanks everyone!