Hornady progressive and general progressive press warnings
Comment made:
Yeah the powder cop die was an extra/redundant check more than anything. I never trusted progressive presses because of the threat of a double charge, but there are steps you can take to prevent that.
The press has auto-indexing (one reason I would never feel safe owning a 550b) so you can't double charge without breaking your rhythm. You must always completely cycle the press (the Dillon 1050 even has a ratchet assembly to prevent any short-stroking). You NEVER partially cycle the press with cases in the shellplate, particularly not under the powder measure. The only way to get a double charge is to short-stroke up-and-down while not paying attention and activating the powder measure 2 or 3 times until you notice the powder spill.
The problem you are really watching out for is having the powder bridge in the powder measure so one case has 80% of the charge and the next has 120% of the charge. This is where the RCBS Lock-Out is such a blessing (or the Dillon Powder check die system). I don't trust just a visual indication as I spend too much time watching the bullet entering the seating die to see how the next case measure up.
Never force anything. If there is a problem, lower the ram, remove all cases, cycle it to see if the fault is with the press or primer feed. Then return one case at a time starting at station 5 and working around to station 1. Almost every problem will be related to case sizing or primer feed problems (this applies to ALL progressives—the primer feed is the weak link of all of them). If you ever find the primer slider not picking up a primer, you have either bent the wire that cams the slider back and forth or the plastic tip at the top where the wire connects to the press has cracked. Again, don't get frustrated, just clear the press and inspect for the problem. If anything ever hit that wire, one of those two problems is likely. In general, Hornady will be happy to send you a new wire and plastic top and replacing is easy.
Next is cleanliness. The press has to kept clean. Compared to the Dillons I have used, the Hornady is much less sensitive. The 1050 almost needs to used in a clean room. However, one change made when they came out with the L-N-L a few years ago was putting the primer seating stem under and screwed into the baseplate. Because they designed the primer seating stem in a "T" shape (to fit a spring), there is the possibility for a speck of powder or dirt to fall into it and keep the seating stem from returning to the rest position. This is a place where if you force anything (and you have the leverage to do it), you not only will destroy the primer seating assembly but you might even be able to damage the baseplate. The Dillon 1050 is less sensitive to this since the designed more of a column than a "T" and it is longer so the "crap" falls out of the way rather than being trapped in a little god-awful piece of kit. Just take it out and blast it with air or pressurized cleaning/degreasing spray (while holding the stem UP).
One final "fix"—I locked the PVC tubing to the spent primer tube and directed the PVC tubing into a trash can so there are no spent primers hitting the floor.