I also have seen many diferent trim to lengths.
If you go by the book the max case length is 2.525 with means your trim to length is .010 less or 2.515
That is the length I trim to for my NCR 280ai
Mostly it depends on the the reamer and the finish chamber. The best way is to chamber cast and find where your throat begins. Then I trim .010' short of that.
