I saw the pinch trim cutter and thought I would post the other version , expand and trim setup .. as for which is best I think it depends on length ? It certainly involves 2 steps vs. only 1 .
By the way Richard Corbin made this one for his walnut hill press , assume he still does .
The only problems I ever had was getting it stuck once in awhile on the spring punch ,external punch after it inserts into the now formed jacket , if not adjusted correctly .