@Toby I found the lee collet press needs a bit of a technique or it seems to be inconsistant in its output, I sort of "bump" it at the end of the stroke. Also a decent press, I found the Lee progressive press for instance allowed so much movement the lee collet die didnt seem to work well, when I switched to a rcbs single stage press no more problems.
I also dont quite understand why a bush neck sizer die wouldnt work with an AI as you are only sizing the neck with it. What I have done is use a 308w full sizing die to necksize a 303british case to use 150gr 308w hornady projectiles with no problem. I just slowly ran it down mm by mm on the first one until 3/4s of the neck was re-shaped, locked it and away I went.
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