klr wrote:Did you guys use pistol brass to discover this?
Yes, for me, anyway. That expander plug will try to keep expanding an expanded cartridge every time it passes through the die. This results in less and less rotation of the drum. If you use a previously sized case, like reusing the case you just tested, and adjust the die in any, the next time you send a freshly expanded case through the station, it will over-expand your case mouth. When the AutoDrum, I crushed one or two cases because I wasn't using a fresh case for adjustments or testing charges.
klr wrote:Also, I'd guess that the type of powder and weight of the charge effects this.
It would have nothing to do with the weight of the charge; the meter on the drum controls the charge. The proper depth of the die reflected via the slider position delivers rotation to drop the charge. As the case is expanded less on each pass, the rotation of the drum decreases, preventing the meter from dumping a full charge. If, while adjusting charges, you keep increasing the volume of the meter to make up for the decrease powder dropped (because the drum isn't dumping completely) when you do send a freshly sized case through the station, it will be overcharged.
I've experienced this enough when the AutoDrum was introduced, I now habitually use only a rest case when I set up the drop (pistol or rifle). I don't use any rifle "flaring" dies. I use Lee custom Ez-Xpanders (full-length pacesetter dies and mandrels (collet dies) to deliver a uniform case neck for the bullet of choice, whether it be on or over spec diameter such as with cast bullets.
With pistol bullets and cases, I make case mouth contact (case in shell holder), then turn the PTED in 5ΒΌ turns, and mount the Auto Drum. This setup is where I start, and it might be a slight adjustment back out for a jacketed bullet. I use a fresh case every time I test it. All my pistol loading is on the Load-Master, so I'm using bullet feeders, this setup has delivered a perfect flare for the bullet fingers to present a bullet to the case for the five pistol cartridges I'm loading.
The same with the 30 Carbine; however, the bullet seating die with the taper at the base of the die for the bullet feeder fingers to mate with is no longer available. My 30 Carbine die set is at least 25 years old. It will be on my bench when I croak.