Regarding stock fit:
I had a 7mm RM in a 77 tanger. It felt terrible until I replaced the stock with B&C. Then it felt mild.
I had a Ruger 416 Rigby that hurt more than it should. I sold it. I probably would have liked that rifle if it were re-stocked. But I pretty much gave up on Africa and Cape buffalo, but if I do go I’ll make do with a 375 H&H AI pre-64 that doesn’t recoil badly, even with full power 300 grain loads.
I like the Ruger design but their stock design doesn’t fit me. I think their comb is too low or maybe because I’m larger than many. (My shirt size is 20” neck and 40” sleeve).
I don’t have the same problem with 70’s or 700’s???
I did feel recoil on my 600 350 RM with full power 250 grain loads but a replacement stock, synthetic and as light as factory made the 600 feel fine.
Some people whine about the 300 Weatherby recoil. I’d bet that if they shot that cartridge in a 700 they would stop complaining about the 300’s recoil.
Ex- BIL had a 7 mag like yours.
He complained about how it kicked,used a jacket to cushion it. Was at our place
frequently zeroing it.
Dad and I decided he was a puss and afraid of it.
Finally, we shot it.
Dad had a Vanguard, I had a Sako. 7mms. That Ruger was brutal.
It hit harder than my 300 Win Mountain Rifle.
Have since noticed the same with other 77s.