I believe that felt recoil is the recoil that is felt. This can be different from actual recoil. The best example I know is – take a 12 gage shotgun and fire it with it held against your shoulder (you will feel the recoil) then take the same 12 gage and fire it with the butt about an inch in front of your nose. The actual recoil will be the same but the felt recoil will be different. DON”T REALLY TRY THIS. For actual recoil you might check here -
http://www.travellercentral.com/rules/ke.html