I know the thread very well and it does not contain the info I am looking for. Ed and I have worked on the 12GaFH project in all its forms for 7 years now. I am using the original 3.85 inch .50BMG brass case blown out to 12ga with my thread on 12GaFH Rims. The case is capable of 55KPSI but in a double it will be restricted to 26Kpsi. -Rob