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How do other systems overcome this problem of varying rim thickness?
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Most systems don't control this "perfectly"... the Forster has a tapered collet, and the distance that it travels to hold the case, determines the case AOL, so the same problem (??) occurs, a smaller rim dia means a shorter case (by the same amount).
I bought the RCBS trimmers (manual and electric) because the holder draws the case back against a fixed stop, and it looked good in theory, but the trimmers were so poorly made that I threw them in the trash after using them for less than a year. I went back to the Forsters (I now have three).
I'm not so sure that the concern of case length differences of +/- a few thou is meaningful (except to an anal compulsive retentive).
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