I measured the Ø of the mandrel in the Lee collet die in .243. 0.239" compared with a new one at 0.241", not much difference perhaps, but the bullet Ø is 0.241".
Dies are secondhand dies so the previous owner sanded it down.
Where do you get for new ones, Tim Hannam and the like I guess?
Trying to reduce the SD of my rounds, hence the check.
The .222 collet die Ø is 0.221" and that I bought new.