With no case in the press, does the die touch the shell holder? For full length sizing, it should, when you look at the open section of the shell holder, you should see the decapping pin, it should
just go past where the base of the empty shell would be. What caliber are you reloading? Are you sure the cases are boxer primed?
This all assumes the expander is breaking at the top of the stroke. If it is breaking when you are removing it from the case, are you lubing the case necks? I find lubing the first one, and every 3rd one is enough to keep things running smoothly.
Any more info from you would also help, ie. which caliber, which press, which brand of brass, etc. The more info, the better, lots of experience around here (not from me though, I'm still just learning too

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