Regarding H380, I never had any issue with temperature sensitivity. Back in those days, I'd never heard of temperature sensitivity, never experienced it in any measurable way, so for practical purposes, it didn't exist: temperature sensitivity hadn't been invented on the internet yet. That's evidence for our propensity to overthink stuff and create problems where there are none.
I tried H414 / Win760 but they didn't work as well with 50s and my first Swift wouldn't shoot 55s or heavier worth a darn.
Regarding seating depth, I wonder if the long sloping shoulder does not center the bullet in the chamber behind the rifling repeatably until we actually shove the bullet into the rifling and let the discharge reshape the case to the chamber as needed. Who knows? Or it could be that the long tapered case doesn't give consistent ignition but shoving the bullet into the rifling increases resistance increasing consistency. Who knows 'bout that, either? Things happen fast in there at 60K PSI.
This in my opinion describes my experience to a tee. Good post.
