I've shot a 50BMG on a mauser magnum action and I didn't ask the gentleman to please let me do try it one more time.
My 350 Rem Mag on a super light Remington 600 with a kevlar stock has hurt me with the scope coming back 'fast and furious'. I've got a much longer eye relief on that rifle now.
But I've never shot most of the heavy kickers you guys are talking about.
I like the Pachmayer Decelerator pads on the rifles I own, including that light 600 and a kevlar stocked 338 I used to own.