I've shot 2 #1's in 460 WBY now. One belonged to icehunter. Thanks, buddy!!! I've also shot 460 WBY in bolt actions rifles. I *think* that's the most powerful cartridge I've shot through sporter weight rifles, and while the recoil was very very real, they weren't horrible. Not sure I would want to do 50 at a bench in a sitting, but not horrible.
I've also shot a hundred 50BMG's, through my rifle but most of the 50 rifles are usually heavy and braked. I dont' like brakes but with the 50 it's ok.
Honestly the most uncomfortable rifles to shoot for me have always been Moison Nagants from prone. Fricking hate those things and I would prefer to shoot 50 375 Ruger than 5 from the Nagant. I still won a shooting competition at one of the Haggisfests with a Nagant, but I hate them.