Thought I would post this here as many shotgunners are not aware of the length difference between crimp types with birdshot or buckshot loads.
The average case length needed is .40" for folded crimp vs .15" for rolled crimp.
So just a bit of illustration:
2.50" - .15" = 2.35" Roll crimp 2.50" hull loaded length is 2.35"
2.75" - .40" = 2.35" Fold crimp 2.75" hull loaded length is 2.35"
2.75" - .15" = 2.60" Roll crimp 2.75" hull loaded length is 2.60"
3.00" - .40" = 2.60" Fold crimp 3.00" hull loaded length is 2.60"