Armbrust tested 1 oz. 2 1/2 Dr.Eq. loads:
Federal Game Load 1 oz at 1161 fps was 9160 psi in 2001
Federal Game Load 1 oz at 1135 fps was 9633 psi in 2002
Winchester (Australian manufacture) Game Load 1 oz at 1161 was 9300 psi
Cheddite for Herters “Select Field Dove and Quail” 1 oz. at 1165 fps was measured at 1,200 fps and 11,500 psi

Obviously components change in 20 years

I communicated with Tom in 2019, he did not use email, and his phone was 815-451-6649