OzFclass

https://www.youtube.com/watch?v=c0t7alD ... sOQbXjrYHY
FYI, only thing I would add is when using brass from another chamber, this is very likely even after sizing.
Matt P

In your line of work as a gunsmith Matt how often do u set the customer up with a FLS die made from a “resize reamer” that matches the chamber reamer used to cut the chamber ? For a competition shooter/customer who wants to ensure everything is right this would seem a smart move ?

I have my gunsmith ZCR in South Australia make me custom Nulon dies with a sizing reamer that is matched to my chamber reamer.
I have one for my 6.5x47, 284 KMR and 7mm SAUM.
They work very well and only size what is needed if made by the guys that know how to do this

Suffered this with some old Norma 280AI brass last week - subsequently it proved to be the last firing for that brass.

If you shoot a 308 (and some others) you can buy a small base die, that may give you enough body resizing to do the trick.( Probably) One thing .... if your brass is old I would either chuck it when you get a new chambering or at least anneal it before running it through the small base. esp lapua brass.