I have reloaded some 20 ga low pressures for a damascus gun based on this formula:
Win Universal shell (same with Win AA/HS according to the cut profile of the shell) Rem 209P, 800X 16.5 gr. and RXP20ga wad with 7/8 oz of lead at pressures of 7500 psi and velocity of 1200 fps.
Is it OK to assume that if I drop the load to 3/4 oz and/or the powder charge to 15 gr. the pressures will be lower?