A couple of things must be understood. Pressure & Recoil are not directly related in the way many assume. Heavy recoil can be generated with low pressure & High pressure may generate low recoil.
Ben-T pretty well has it summed up. Pressure is of concern primarily to the chamber of the gun,ie wall thickness in that area. Frame flexing, stock cracking etc are all dependant on the recoil.
Charge wt and/or velocity determine recoil. Powder burn rate vs charge wt determine pressure.
Incidently there are dangers involved with pressures being either Too high or "Too Low". Any gun I do not feel comfortable using loads of up to 8K psi, I hang on the wall.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra