...anyone happen to know the recoil/pressure differences (assuming an 8.5 pound double) between at 9.3x74r, .375hh mag. and .375 flanged magnum?...

...tia...

I have a 9,3x74R Chapuis double rifle [ 7 1/4 lbs without scope] and I have owned 4 different 375 H&H rifles. The 9,3 has less recoil. I much prefer the 9,3 double to the 375 bolt rifle.

I have a 9.3x62 and 74 as well as 3 375 H&H and 376 Steyr. Either one of the 9.3's is significantly less than the 375's.
My Valmet 9.3x74 is very pleasant. The CZ 550 is not bad either.
The CZ 9.3x62 is my all around rifle.