I have bigger calibers, but for felt recoil, muzzle blast not withstanding, the 375H&H is the heaviest kicker I have ever fired.
Was it just the rifle or do you think you'd find 458 Lott unbearable in any rifle?On further thought,the .458 Lott left the biggest impression. 500 grain loads at 2300 fps. Four rounds and I had a flinch I'm still not completely over. That cartridge really belts you. It makes the .375 H&H feel pleasant. I think my recoil tolerance threshold is probably .375H&H.
My 16 gauge Cooey is the one I found the most unpleasant to shoot. I have wondered sometimes if it was that the gun didn't like the load of shell I was shooting and experimented with other guns of mine. It doesn't seem to change with them or the 16 gauge Cooey. That gun is terrible for kicking and I do a lot of field shooting a year with other gauges but have never found anything that compares to the 16 gauge Cooey......OUCH!!!