I would like to try to use Redding body dies with Lee collet. I am not sure if this is what you are using...
https://www.midsouthshooterssupply.com/item/0007675446/6half-creedmoor-body-die
https://leeprecision.com/collet-neck-sizing-die-only-complete.html
I plan to order parts from midsouth...