Gunner Asch fired this volley in
:

That I cannot tell you. Do you have any documentation? One assumes that
there is an operating regulator on the brake feed? Id say it should be
no more than 30-45 lbs..but thats simply what Ive seen elsewhere.

Gunner

The book for the R2E4, which has the same brake, says 85-125psi into the
main system regulator, and the internal regulator set for 75psi.

LLoyd