Worst kick from a rifle was a straight stocked 30-06.. beat me to a pulp. And cause it was just an -06, I kept trying to shoot it, cause surely it was a freak occurance.. after several different boxes of ammo, even a light handload, it was time to say "Hasta La Vista, Baby.." and off it went.
I have shot up to a .460 Wby, as I used to sight in rifles for a gun shop, and off the bench, anything above .400 is thumping, violent but not brutal. I have never found shotgun recoil, even with 10 guages, to be particularly problematic.. except for that one shot I took at a goose with my shoulder buried in the terrace. That hurt a bit..
Adios,