Greg, I'm no expert but with my .280AI the standard cartridge case had about a .004 "crush" fit in the chamber...stiff bolt closure. There was no need to jam the bullet to hold the case rearward because the shoulder of the case held it back. I fireformed with loads just below standard .280 max... after several reloads i haven't had to resize yet. Not sure as to why your fireformed cases are too tight.
mm
As MM242 Said Most AIs headspace on the neck shoulder junction and not the datum line .
Depending on how your smith chambered and head spaced, determine how the first firing
case fit is.
As stated there should be no reason to use the bullet to head space.
Rounded shoulder edges are a sign of lower pressure, I would back the bullet off he lands and
up the powder charge to the middle of the recommended loads.
Lapua bras is tough and this is not uncommon on the first firing. after fire forming size only
enough to close the bolt on the round.
The reason the brass is tight is the brass was not formed well and spring back aloud the case to
return to a larger size, Or you have the dies set two tight and need to re adjust them.
Setting up to load/fire form AIs takes time and patients but is well worth the time if done right.
Depending on the chamber, some dies are just not the correct dimensions for it. (Sometimes a
neck sizer is nessary to get the best fit in a custom chamber.
Just some ideas to help.
J E CUSTOM
