After failing since 2003 I've got a 223 Lee Collet die working. Neck sizing The decapper pin/mandrel is out of the die-decap first, no mandrel. The die is screwn down until the collet touches the raised shell holder, the collet is the item hanging out of the die body. The lock nut-not the die- is turned so a flat is facing me square on. The die with lock nut is turned down 4 and a half flats, four flats then so the next point on the nut faces me. With 14 tpi and 6 flats this is 3/4 of a turn or ~ .054". The die is taped in place with masking tape so it won't rotate while sizing. Cases are neck sized, the press handles go over-center and click to a stop. I know the necks are sized ~ the same because when they go through the Lyman M die, next step, they all have about the same resistance dragging over the M die expander/flarer thing.
Crimping case mouths Mandrel/decapper still out of the die. The die is screwn in maybe 2-3 turns after the collet touches the raised shell holder. Way beyond where the press could ever go over center. Loaded case in, raise ram, squeeze twice quick, turn 1/4 turn, squeeze twice again, next loaded case. Very fast, little work required.
I know it's crimping because the crimped case neck/mouth measures .003"-.005” less after crimping.
Works for me.