Maybe try annealing the necks, so they squeeze back down easier.
Cant see what good that would do, Lapua cases come annealed and they have not been fired
They've not been fired, but they've been stretched....as in a degree of work hardened. Annealing won't hurt a thing.
I guess boatanchor doesn't understand. The OP seems to be having issues getting the necks sized back down. It doesn't matter if it's been "fired". It's been worked more than it should have been, by running the 6.5 expander through the neck. That causes unnecessary "work hardening". This is the reason I suggest a little annealing. I shouldn't have to write that out, as an explanation: As, most guys get it. Maybe? Maybe not?
Maybe.
Maybe not.
You're right that they've been over expanded, and likely way more than having been fired. Not to mention, once sized back down the brass will have been moved in that procedure way more that being normally sized. They're going to likely need annealing anyway at that point. When I make 243s out of 308s I anneal in all 4 steps. Smooth as butter each step and the brass stays where I put it.
And, for redundancy, all brass is annealed to some factory spec before it goes in the box. Lapua isn't the only one, they're just one of the few that doesn't process off the evidence. Moving brass molecules cold in any way begins the work hardening, and it compounds until it fractures, or is annealed.
Suggesting the OP anneal these cases only makes sense, as softer brass will form easier. It's only 20 pcs for Christ's sake, light a candle if you have to.