I know this is old but if I recall the rifle was a Ruger RSM. Those stocks beat me up more than anything else I have shot. My CZ 550 in 458 Lott was very comfortable compared to the RSM 416 Rigby. That one hurt after 6 shots. The 458 Lott RSM i only took 2 shots out of and sold it. I could shoot 19 fairly hot .458 loads with the CZ no problem and actually have fun shooting it.
Definitely true in my experience. Stock fit is crucial.
My first >.40 bore DG rifle was a CZ 550 .416 Rigby with the American stock. I worked up handloads to 2300 fps, shooting maybe 250 rounds.
The Ruger RSM rifles are great design except for the stock, (and possibly the ejector mechanism when worked at speed). Aesthetically, they are one of the finest rifles made in the American market.
Some rifles are like women, beautiful and eye catching, but treacherous.
So, a Ruger RSM .416 Rigby caught my eye, and I traded the CZ and too much cash for the Ruger.
While I was proficient with the CZ, that Ruger beat the piss out of me. The recoil was stunning, literally, in that after the first shot, cycling the bolt from my shoulder was difficult as my arm went numb. So, I sold it.
The RSM in 375 H&H is not too bad in recoil, as it is so heavy. A lighter, well-fitting Winchester 70 Alaskan .375 is much easier to shoot for me, even with the Monte Carlo stock, it just fits.
Whitworth Interarms Mark X are my favorite DG factory stocked rifles. They just fit me.