Progressives are no worse then single stages. It all boils down to one simple rule.
After charging the case with powder, look in the case and put a bullet on top of the case right after you look in the case. Problem solved. It's now impossible to double charge the case with a bullet on top. Works on the 550 as well. Put the bullet on the case after looking in the case and before you index the press. Simple and safe.
Yes, I post using a phone so my spelling sucks.
Converting Hornady owners to Dillon
one owner at a time.