I use 36 grs of H380 and a cheap 100gr bullet seated out to the lands.
It realy doesen't matter with a ture Ackley case as the headspace doesen't change , so realy simply firing any factory ammo will make a formed case.
I had a cheap Adams & Bennet barrel chambered at the same time as my custom tube so I used it to fire form all my brass , then when I was done I unscrewed it and screwed on the Hart and bingo , 500 pieces of fire formed brass and zero barrel wear.