After nearly 20 years and over 20,000 rounds on a single stage press, I made the plunge and got a progressive press, the Lee Loadmaster. It was a big step up but I never trusted the priming function, so did those all manually, which took away from the efficiency and speed gains I had hoped for.
Then came the Six Pack. What a huge and positive difference.
I found that taking care to set it up in the right sequence and to closely and deliberately watch four stations in particular leads to nearly flawless operation.
I'll start with the only slight downside I have found in the system, simply because it explains why I went about testing the stations the way I did. That only downside is that things get a little tight between some of the stations, particularly the powder station and the bullet feed station. It will fit, but you have to have things aligned just right or the vertical movement of the powder drum can bring it into contact with the bullet feed. Align it correctly, though and it's flawless.
First thing to do is to test the bullet seating station. Do that first with no other dies or elements on the press and make sure that it is set up to the specs you want. You do NOT want primers in place at that station, you do NOT want the powder or bullet feeds in place when doing that.
Secondly, test the bullet feed station, again with everything else removed (in my experience). Make sure that it's seating in the cases the way that you want it to, especially so that the bullet remains upright in the cartridge before seating.
Thirdly, and again with no other dies in place, test the powder charge for weight. Try 3 or four in a row. If you choose the right station for the powder feed, it will be easy to remove the filled cartridge by sliding the holder tab back. This avoida spelling powder when it is eventually elected if you don't remove it.
Once all of that is done, add the bullet feed (leaving the powder station that you just Tested in place.) Try to make sure that the plastic sites of the powder die are pointing as directly outward from the centre of the circle as possible. Then add the bullet feed setup (with no bullets in it) and cycle to make sure that the powder and bullet feet setups aren't hitting each other. Then add the seating die, the sizing die and, if your using one, the Universal decapping die.
When running it, my mantra became "Primer upright, case upright, bullet upright and visible powder charge". On EVERY single charge, I made sure that the primer arm had an upright primer, I checked that the new case that had been added was upright, checked that a bullet had fed and not fallen over and verified that the case about to receive a bullet had received a powder charge.
Once got into that rhythm, I ran several thousand cartridges in very short order without a single problem. I caught instances where primers were upside down or where they hadn't fed. I caught cases that had exited upside down. I caught several instances where the bullet feed tube had emptied and no bullet had fed. I caught the occasional instance where the bullet had "leaned" and would not have crushed the case if I had pulled the lever. By doing that simple mantra of looking at and confirming that the primer was in the primer arm, the new case was upright, the bullet was positioned for seating, that a bullet had dropped from the feeder and that powder had been dropped into the previous case, this system was literally flawless.
Cannot say enough good about it.
Brilliant!