The instructor I've taken a couple of long range classes from shoots a variant of the 6.5x55. I don't recall the name of it but it's got a blown out case and a 37degree shoulder. The 140gr class bullets need to be seated deep in a short action but he has good success with it in PRS matches. After initial case prep and fire forming all he does is clean and reload, no trimming or chamfering required, just anneal the necks ever few firings (Lapua brass of course).

Edit: the cartridge is the 6.5 Addiction, PTG lists the reamer.