I have both the Redding dies and the Forster trimmer. I have not had that issue.
it is however really, really easy to deform the case mouth on the sizing die's expansion ball.
I just measured the trimming pilot: 0.471
a sampling of sized cases also measured 0.471 inner diameter and 0.473 right at the lip
the cases slipped right on though.
a sampling of Woodleigh softs measured 0.474 on the shank, 0.468 at the base(bevel)
