To 'measure' recoil you will need to suspend the firearm from supports that will let it swing and know the weight of the gun and then measure the actual displacement during firing.


To 'measure' presure, you will need a transducer that is calibrated in a chamber connected to a recording device.

'Measurement' is not calculation which I believe you are discussing, PeteM.

To calculate recoil, the mass of the charge has no bearing and is not included if indeed it is calculable.
To calculate pressure, "the plasticity of the barrel" has no bearing and is not included.

It is not simple Physics. -Dick