I to have been testing out of my multiple dashers and putting them through the ringers. I did the same procedures as you. Light load first initial time and all was good from there on. I have been pounding on the brass and loading them hot. I have kept every target and have currently (36) firings on the brass and still running them with no issues.Lapua formed to dasher goes through a soft firing or two to get formed. If you soft fire Alpha once or twice, it does the same thing, that is, work harden.
As far as the difficulty in seating a primer, yes, it takes a firing to loosen a bit so that you can seat easily. At the same time, it’s hardening like lapua as it distorts.
I’ve pushed this stuff pretty hard and haven’t had issues. Bad luck on messing up your rifles. Through 3 lots of this stuff and haven’t had a hiccup.
It is chamfered, however. My original point stands. Take a K&M uniformer and see how much material is removed.