Hope you guys don't mind me trying to help you out.

450 Marlin with a 350 grain bullet has 37.2 recoil energy
300 Win. Mag with a 180 grain bullet has 25.9 recoil energy

According to this chart, the .450 kicks a lot more. Here's a link to the site where I found the info.

[link]http://www.chuckhawks.com/recoil_table.htm[/link]