There is a link on Chuck Hawk's website that has a recoil table.
http://www.chuckhawks.com/recoil_table.htm
I have a Remington 870 12GA, a Savage .308, an old Marlin .30-30, (and my old boyhood Marlin .22 rifle now owned by my daughter).
Put some 00 Buck in my Rem 870... It'll thump me really good
Put a slug in my Rem 870... It'll kick the crap outta me.
My .308 rifle has nowhere near the recoil of my 12GA!
The old .30-30 is sweet and doesn't kick at all.