375 isn't really considered big bore, it's on the top end of medium bores. The difference in recoil is pretty significant, so I'd imagine the chambering makes a difference.
Do the 550 Magnum rifles in .375 have a second recoil lug on the barrel? How about in the bigger calibers?
As mentioned, bedding is never a bad idea. And cross bolts also. I always install internal cross bolts when I'm building a stock for a heavier recoiling rifle.



























