MMAM,
Set the die up so it touches the shellholder and back it off a couple turns.
Lube the case and run it in and see if it chambers, it probably won't.
Turn the die down an 1/8 turn each time and try it again until it finally chambers easily.
Back the die off a 1/16th turn and see if it still chambers easily, if it does, run the case up in it agin and tighten the lockring on it there.
If it doesn't, turn it back down 1/16th turn and run the case up in it and lock it down.
Often refered to as "partial FL sizing", basically keeps the shoulder from bumping back farther than necessary creating excess headspace.
Yours has a belt, so that isn't happening any way but, it still will keep from working the shoulder area as much and offers better alignment by way of keeping the shoulder tight. Seating the bullets into the lands is best for that though.
That's what I do "if" I "need" to FL size. Get a good neck die and this will do more for case life than anything, especially if you keep them annealed every three to four rounds.
What are you shootin, maybe a 7mag?